Receiving unit 111 of exemplary friend candidate management server 10 receives from a first information-processing device, identification information of another user registered by executing a first program. Storage unit 12 stores the received identification information of the other user. Sending unit 113, for presenting to a user by executing a second program different from the first program, sends to the first information-processing device or a second information-processing device different from the first information-processing device, the identification information of the other user stored in the storage unit or another item of identification information corresponding to the identification information of the other user. The identification information of the other user is registered in the first information-processing device as friend information of the user based on a mutual agreement between the user and the other user.