To enhance the efficiency of packet communication by wireless between apparatus conforming to the USB standard.

A number of occurrence of packet corruption count time register (Reg1) for setting the number of occurrence of packet corruption count time, and a number of occurrence of packet corruption counter (Reg4) for counting the number of occurrence of packet corruption within a set time of the number of occurrence of packet corruption count time register are provided. Efficiency of packet communication is promoted by further providing control units (10, 111) which decrease the bit rate in the packet communication when the number of occurrence of packet corruption obtained in the number of occurrence of packet corruption counter is or above a predetermined reference value, otherwise increases the bit rate.