A remote maintenance system comprising: a monitoring computer for monitoring a facility to be maintained; and a monitoring center computer for monitoring information held with said monitoring computer and sending maintenance information to said monitoring computer, through pay station line, wherein said remote maintenance system is characterized in that said monitoring computer has a database for storing image data of said monitored facility, and said monitoring center computer includes: a database for storing CAD data for said monitored facility; a function for providing coordinates to said image data sent from the monitoring computer to form image coordinate data; a function (19, 80) for superposing said image coordinate data and CAD coordinate data for said CAD; and a function (19, 81) for locating a needed maintenance spot being 3D data of a member having a deterioration and/or a deformation exceeding a tolerance value on the basis of a result of said superposition processing and sending information of the located maintenance spot to said monitoring computer, and wherein the function for locating a needed maintenance spot (19, 81) has an intolerable apparatus coordinate recognition function for recognizing the member having a deterioration and/or a deformation exceeding a tolerance value based on the superposed image coordinate data and CAD coordinate data and based on information being sent from a main-member tolerance difference database storing tolerable tolerance values of the deterioration and/or the deformation of a member; wherein said system further comprises: a tag having a storage and being installed in said monitored facility; and mobile equipment being connected with said monitoring computer through pay station line, wherein said mobile equipment has: a function for receiving said tag-stored information via radio communication; and a function for sending the received tag information to said monitoring center computer, wherein said monitoring center computer further has: a database for storing said maintenance information for said monitored facility; a function for receiving said tag information sent from the mobile equipment; a function for retrieving said maintenance information from said database on the basis of said tag information; and a function for sending said retrieved maintenance information to either said mobile equipment or said monitoring computer, or both. a monitoring computer for monitoring a facility to be maintained; and a monitoring center computer for monitoring information held with said monitoring computer and sending maintenance information to said monitoring computer, through pay station line, a database for storing CAD data for said monitored facility; a function for providing coordinates to said image data sent from the monitoring computer to form image coordinate data; a function (19, 80) for superposing said image coordinate data and CAD coordinate data for said CAD; and a function (19, 81) for locating a needed maintenance spot being 3D data of a member having a deterioration and/or a deformation exceeding a tolerance value on the basis of a result of said superposition processing and sending information of the located maintenance spot to said monitoring computer, and wherein a tag having a storage and being installed in said monitored facility; and mobile equipment being connected with said monitoring computer through pay station line, a function for receiving said tag-stored information via radio communication; and a function for sending the received tag information to said monitoring center computer, a database for storing said maintenance information for said monitored facility; a function for receiving said tag information sent from the mobile equipment; a function for retrieving said maintenance information from said database on the basis of said tag information; and a function for sending said retrieved maintenance information to either said mobile equipment or said monitoring computer, or both.