A hydraulic pressure control device includes an accumulator configured to accumulate oil supplied by a mechanical pump and discharge the accumulated oil to a control system; a first oil path connected to a hydraulic path (clutch oil path) at an upstream side than an SLC linear solenoid; a second oil path connected to the hydraulic path (clutch oil path) at a downstream side of a manual valve; a connection control unit (switching valve, accumulation control valve) configured to control the connection between the accumulator and the hydraulic path to communicate the accumulator to either one of the first oil path and the second oil path; and a back pressure control oil path configured to supply the oil supplied by the mechanical pump to the back pressure side of the accumulator.