To prevent the laundry from being stolen by a method wherein in a coin type washing machine, which is operated by putting coins into the machine, after a user puts coins into the machine, washing, rinsing, and dewatering processes are controlled and a cover locking means for locking a cover is controlled to prevent the cover from being easily opened during operation so that a following user is prevented from erroneously putting objects to be washed or cabins into the machine.

It is sensed by a coin input sensing means 3 that coins have been put in to control the start of operation and a washing and dewatering tank and an agitation vane disposed in the tank are driven by means of a motor 12 and washing, rinsing, and dewatering processes are controlled by a control means 17. A cover locking device 19 is provided to cover the upper part of the tank with a cover, and the washing, rinsing, and dewatering processes are controlled by the means 17 and the action of the device 19 is controlled.