To uniform the operating times of first and second drain pumps by a simple circuit and at low cost.

In an automatic mode, connection switches 106a, 206a, 302 are closed. Each time a series of drain operations by one or both of the first and second drain pumps are completed, a ratchet relay 112 is alternately brought into a first state (switches 113, 214 are closed, and switches 213, 114 are open) and a second state (switches 213, 114 are closed, and switches 113, 214 are open). In the first stage, a switch 115 is closed at a first water level, and the first drain pump is driven by a motor 17A so that it is brought into the operating state prior to the second drain pump. In the second state, a switch 215 is closed at the first water level, and the second drain pump is driven by a motor 17B so that it is brought into an operating state prior to the first drain pump.