1. A behavior improvement system comprising: a person-in-charge terminal consisting of a computer installed on a side of a person in charge who administers a behavior improvement by setting a goal target of a member and makes a determination as to whether a goal is achieved; an advisor terminal consisting of a computer installed on a side of an advisor who is registered, as needed by the person in charge, as an advisor making the determination as to whether the goal is achieved on behalf of the person in charge; a member terminal consisting of a computer installed on a side of each of the members; a diagnostician terminal installed on a side of a diagnostician who answers a questionnaire of the behavior improvement of the member; and an organization computer as a server computer arranged on a side of an organization, the organization computer connected via a computer network to the person-in-charge terminal, the advisor terminal the member terminal, and the diagnostician terminal, the organization computer requesting the member terminal and the diagnostician terminal for a diagnosis of an action plan of the behavior improvement of the member, wherein the organization computer includes: a recording means to which identification information identifying the member terminal is recorded; a self-checking execution means consisting of a function for recording to the recording means, in association with the identification information of the member terminal, a self-checking screen including a free description field allowing input of a comment of the member with respect to the action plan, a function for calling up the self-checking screen from the recording means and for sending the self-checking screen to the member terminal corresponding to the self-checking screen, and a function for recording to the recording means, in association with the identification information of the member terminal, self-checking result data with respect to the self-checking screen inputted by the member terminal and data inputted to the free description field; a diagnosis interview sheet setting means for recording to the recording means, in association with the identification information of the member terminal, a diagnosis interview sheet screen consisting of a question for a diagnosis inputted by the person-in-charge terminal, a plurality of alternatives as a reply to the question and a point allocated to each of the alternatives, and a comment field allowing input of a comment of the diagnostician; a diagnostician setting means for allowing, upon an input from the member terminal, selection of a plurality of addresses from among an address list of terminals previously recorded to the member terminal and for recording to the recording means, in association with the identification information of the member terminal, the terminals corresponding to the plurality of selected addresses as a plurality of diagnostician terminals; a diagnosis execution means for calling up the diagnosis interview sheet screen from the recording means and for sending the diagnosis interview sheet screen to the member terminal corresponding to the diagnosis interview sheet screen and to the plurality of diagnostician terminals recorded to the recording means in association with the member terminal; a function for storing each of reply information to the recording means in association with the identification information of the member terminal, upon an input of the reply information on the diagnosis interview sheet screen from each of the member terminal and the diagnostician terminal corresponding to the member terminal and comment data for the comment field from the diagnostician terminal; a function for displaying a degree of a gap of replies between the member and the diagnostician by comparing a point assigned to a reply inputted by the member terminal with an average point of points assigned to replies inputted by the plurality of diagnostician terminals upon calling up the reply information from the recording means, and a function for calculating an achieving rate of the member by comparing the average point inputted by the diagnostician terminals with a reference point previously defined; a function for recording to the recording means, in association with the identification information of the member terminal, a diagnosis interview result screen displaying a point inputted by each of the terminals, the degree of the gap, the achieving rate, and the comment data of the diagnostician inputted to the comment field for each of the questions; a diagnosis interview result generation means consisting of a function for calling up the diagnosis interview result screen from the recording means and transmitting the diagnosis interview result screen to the member terminal corresponding to the diagnosis interview result screen; an advice request means for, upon an input of advice request information from the member terminal, calling up from the recording means and sending to the person-in-charge terminal or the advisor terminal the diagnosis interview result screen including the comment data of the diagnostician recorded in association with the identification information of the member terminal and the self-checking result data and the comment data of the member written to the free description field recorded in association with the identification information of the member terminal, and for transmitting to the person-in-charge terminal or the advisor terminal a mail requesting for an input of an advice; and a goal achievement recording means for recording a notification of a goal achievement in association with the identification information of the member terminal inputted from the person-in-charge terminal or the advisor terminal having received the mail requesting for the input of the advice, wherein the person-in-charge terminal or the advisor terminal having received the mail requesting for the input of the advice has a notification transmission means for transmitting to the member terminal the notification of the goal achievement by the person in charge or the advisor or a notification of an advice of a new action plan execution due to a goal non-achievement.