Provided is an air conditioner that suppresses power consumption by discharging resistors for discharging residual charges of a transmission path. An analog switch is previously interposed between two discharging resistors. In sending an AMI signal to two lines of a transmission path, an MCU executes discharge control to cause the analog switch to achieve an OFF state when a high level signal voltage is output, and to cause the analog switch to achieve an ON state when a low level signal voltage is output.