Provided is a hydraulic pressure control device. A hydraulic pressure control device includes a solenoid valve configured to supply hydraulic pressure to switch between an engaged state and a released state of a lock-up clutch, and a transmission control device configured to control the solenoid valve. The solenoid valve supplies hydraulic pressure to switch between a parking locked state and a parking released state of a parking lock mechanism, in addition to switching of the lock-up clutch.