To provide a server device, a navigation device, system, method, and program quickly and positively converging a plurality of movable bodies.

In the navigation system, the server device 1 and the navigation device 2 of each movable body are connected by the Internet N and a mobile telephone network K which is a telecommunication network. A sending and receiving part 11 of the server device 1 receives pieces of identification information mutually associated so as to compose a group, and each position from each navigation device 2 via the telecommunication network. A convergence point calculating part 12 calculates a convergence point of each movable body on the basis of each received position. The sending and receiving part 11 sends data of the convergence point calculated by the convergence point calculating part 12 to each navigation device 2 having the identification information.