In order to reduce the amount of time from when signals are sent to solenoid valves 19, 23, 24 for adjusting hydraulic pressures inside hydraulic pressure chambers of various hydraulic devices 7, 8, 14 assembled in a continuously variable transmission device until the hydraulic pressures are actually changed is shortened, the solenoid valves 19, 23, 24 adjust the hydraulic pressures inside hydraulic pressure chambers connected to hydraulic introduction paths where the solenoid valves 19, 23, 24 are provided by adjusting apertures of the solenoid valves 19, 23, 24 set according to duty cycles, and a controller 16 for the solenoid valves 19, 23, 24, when the apertures of solenoid valves 19, 23, 24 are changed beyond specified values to desired apertures, adjusts the apertures beyond the desired apertures to a state where the apertures have been changed a maximum amount, then after a specified amount of time, returns the apertures to the desired apertures.