A hydraulic pressure controller is used to control output pressure of a solenoid valve in an oil-hydraulic circuit of a transmission of a vehicle. The hydraulic pressure controller includes an operation value setting section and a correction section. The operation value setting section sets a duty cycle of an operation signal based on a target exciting current and an actual exciting current of the solenoid valve. The operation signal is inputted to a driver circuit for driving the solenoid valve. The correction section corrects the duty cycle, the target exciting current, or the actual exciting current by using a filter for eliminating or damping a resonant frequency component of a vibration model of the output pressure.