A pump includes a housing that has a compression chamber for pressurizing fluid and a fluid passage for guiding fluid into the compression chamber. A valve is located midway through the fluid passage for communicating and blocking the fluid passage. A solenoid actuator is located on a substantially opposite side of the compression chamber with respect to the valve for operating the valve. A regulating member is located between the valve and the solenoid actuator for regulating pressure of fluid in the compression chamber from being applied to the solenoid actuator.