To provide a washing system for a laundromat which has an ability to pull in more customers during the periods when the washing system is used less frequently.

A control section 11 calculates a utility rate by subtracting a correction amount from a basic rate corresponding to each course. The control section 11 memorizes the number of times that a washing and drying machine 1 is used by day of the week and by time zone, and realizes less frequently used periods based on the number of times that the washing and drying machine 1 is used each day of the week and in each time zone. For the periods when the machine is used less frequently, the correction amount is set larger. Since the utility rate is set low for the less frequently used periods, more customers can be pulled in for such periods.