To prevent the generation of a trouble due to the simultaneous shut-off of all equipments in a multi-connection system connecting plural equipments.

A power supply part interface 100 judges an IDLEo* signal 112 indicating whether a body 350 is in a stand-by state or not and an IDLE signal connected to another station, and when the body 350 and the other station are in stand-by states, turns an IDLEi* signal 111 to a low level. A timer control part 101 detects the low level of the signal 111 and sets up previously set time on a timer 102 to start the timer 102. After counting a set count value, an output signal 110 from the timer 102 is changed. At the time of detecting the change of the output signal 110, a power supply switch control part 103 shuts off a power supply switch 104.