To provide a water level sensor capable of securely sensing a water level in a water storage part of condensate generated at drying clothes with an inexpensive constitution.

The washing/drying machine is provided with: a washing tub 3 for housing the fabrics, objects to be washed and dried, to wash/dry them; a dehumidifier 6 for dehumidifying humid air; a blowing device 12 for sending the humid air inside the tub 3 to the dehumidifier 6 when drying the fabrics; the water storage part 23 for storing the condensate generated in the dehumidifier 6; a drainage device 24 for draining water from the storage part 23; and the water level sensor for sensing the water level inside the storage part 23. At least either one of operations of the dehumidifier 6 and the drainage device 24 is controlled according to an output sensed by the sensor. The sensor is provided with a pair of water level sensing electrodes 40a and 40b disposed inside the storage part 23 and an oscillation circuit 43 having a pair of the electrodes 40a and 40b inserted in a feedback circuit, sensing the presence/absence of water between the electrodes 40a and 40b from a change in oscillation frequencies of the circuit 43 through a change of a feedback current according to an electric resistance between the electrodes 40a and 40b.