1. A data search method comprising: providing, for use in a data search, a search string that includes a space; and searching a data storage for data by performing an AND search that matches all of keywords in front of the space and behind the space in the search string with the data, wherein the data search is performed by keywords having the space in the search string excluded therefrom when a preset condition for the search string that includes the space is fulfilled, and the preset condition is fulfillment of a first condition and a second condition, the first condition defined as acquisition of a number of data in the data storage, the data including one string in front of or behind the space in the search string is acquired as a number of search object data, and the second condition defined as the acquired number of data in the first condition exceeding a predetermined threshold.