To provide a liquid pressurizing device that can be frequently started and stopped regardless of the operation load state of a pump and to provide a system for efficiently controlling the device.

Pump load protective constitution is adopted to this liquid pressurizing device provided with a liquid pressurizing part composed of a plunger and a cylinder to pressurize a sucked liquid by the reciprocating motion of the plunger; a rotary-linear motion converting means for reciprocating the plunger; a servo motor direct-coupled to an input shaft of the rotary-linear motion converting means to apply rotation to the input shaft, and a pump driving control means for controlling the drive of the servo motor. Further, the pressure valve discharged from the liquid pressurizing part is measured to perform the feedback control of output shaft rotation of the servo motor.