To insure the communication quality best suited to the type of data between a transmission system and a receiver.

In the present invention, a transmission control section 52 of a server 51 controls the number of times of resending a packet of transmission data to be sent from a data sending section 13 of a base station 4 in accordance with the type of contents requested from a mobile radio terminal 53 (moving image data, text data or audio data and the like). Namely, the transmission control section 52 of the server 51 sets the large number of times of packet resending in a case where high-reliability data communication is required, in accordance with the type of contents, but sets the small number of times of packet resending in a case where high-speed communicability of a short delay time is required rather than reliability, thereby insuring the optimal communication quality in response to the request of type-designated contents from the mobile radio terminal 53.