To enable a device having a motor in waterproof structure to prevent water from entering the motor even when washed right after operation.

The motor 14 of a conveyor which conveys articles is made waterproof by a waterproof cover 17. The motor 14 is connected to a control means in a housing 25 through a power supply control cable 23a and driven and controlled. Along this power supply control cable 3a, a hollow pipe 23b is provided. One end part of the hollow pipe 23b is led out in the waterproof cover 17 and the other end part is led out in the housing 25. If the device is washed for cleaning in a heating state right after the motor 14 operates, the air pressure in the waterproof cover 17 is to vary suddenly owing to quick cooling, but the air pressure variation is absorbed on the side of the housing 25 through a ventilation pipe 23b to prevent water entering the motor through a weakly waterproof part of the waterproof cover 17.