To confirm whether a destination mate of the received data is agreed with a present user or not in reference to the characteristic information of the user, and to output the received data under a condition of the identification, when the data transmitted through the network is received and output.

A receiving-side host device 1 takes a picture of the present user during log-in to acquire a face image, and further acquires the face image corresponding to the destination mate of a received message in reference to a face image file 11, when it receives the message transmitted from a transmitting-side host device 1. Then the face image of the destination mate is compared with the face image of the present user, whether the destination mate is agreed with the user or not is discriminated, and the message data of the received contents is displayed and output only when the agreement is discriminated.