1. A monitoring system, comprising: a monitoring computer for monitoring a facility; a monitoring center computer coupled to said monitoring computer for monitoring information of said monitoring computer and transmitting information to said monitoring computer; a plurality of mobile equipment each connected to said monitoring computer by a communication line; and a database used for storing manual work item data of a manual prepared for work to be done by a worker, said monitoring system characterized in that: each of said mobile equipment has: a display means for displaying said manual work item data stored in said database; and a work-item input means for inputting a work item of a work condition as a condition of said work done by said worker; said monitoring computer has: a reception means for receiving the work item of said work condition from any one of said mobile equipment; and a condition transmission means for transmitting the work item of said work condition to said monitoring center computer; and said monitoring center computer has: a procedure verification means for comparing the work item of said work condition entered from any one of said mobile equipment with said manual work item data stored in said database; a work-site verification means for identifying a specific mobile equipment corresponding to a work site of a work indicated by a comparison result produced by said procedure verification means as a state of work with the work item of said work condition thereof not matching said manual work item data; and an error transmission means for, when there is a procedure error by the worker wherein the procedure error corresponds to the work item of said work condition not matching said manual work item data, transmitting error recovery information of a manual work item data for a recovery from said work procedure error to said specific mobile equipment corresponding to a work site at which the work item of said work condition thereof does not match said manual work item data so that the error recovery information is shown on said display of said specific mobile equipment.