PURPOSE: To realize the method for reducing a relay time by turning on a power supply for a data reception section and a data transmission section at the start of relay of a relay station and turning off the power supply at the end of the relay with respect to the method reducing the relay processing time of the relay station relaying data between a master station and a slave station.

CONSTITUTION: The station is provided with an antenna connection section 123 connecting an output of a data transmission section 121 to an antenna A or a termination resistor R and an antenna connection control section 124 outputting a control signal controlling the connection of the antenna connection section 123, and when the start of relaying is discriminated, the power of the data transmission section 121 is turned on and an output of the data transmission section 121 is fed to the antenna A at data transmission and the output of the data transmission section 121 is connected to the termination resistor R when the data transmission is stopped and when the end of relaying is discriminated, the power of the data transmission section 121 is turned off.