a user position information receiving unit that receives user position information having position specifying information and a user identifier, for two or more users, respectively;

a processing unit that stores the position specifying information in association with the user identifier, for the two or more users, respectively;

a map expression data storage unit in which two or more pieces of map expression data expressing a map are stored;

a position specifying information storage unit in which the position specifying information for specifying positions of the two more users, which is stored by the processing unit, is stored in association with each of the two or more pieces of map expression data, respectively, and with one or more conditions;

a request instruction receiving unit that receives a request instruction, which is an instruction to transmit map expression data and contains specifying information for specifying map expression data, from a terminal apparatus;

a data acquiring unit that acquires map user information having the map expression data specified with the specifying information contained in the request instruction, and two more pieces of position specifying information corresponding to the two or more users associated with the map expression data, and that generates position added map expression data by adding two or more positions corresponding to two or more pieces of position specifying information of the two or more users to the map expression data, wherein the data acquiring unit acquires the two or more pieces of position specifying information of which one of the one or more conditions satisfies a predetermined condition which allows adding a position specified with two or more pieces of the position specifying information is to be shown on the map expression data; and

a transmitting unit that transmits the position added map expression data to the terminal apparatus, wherein:

the predetermined condition is a state in which the map expression data are being displayed on the terminal apparatus and one or more other terminal apparatuses, which correspond to the two or more positions.