To provide a vacuum pump for motor vehicle having a simple configuration without increasing drive loss of an engine.

This vacuum pump 1 generates negative pressure to ensure assist force of a vacuum type brake booster 3 increasing stepping force of a brake pedal 2. A piston 12 supported by a spring 14 is arranged in a case 11, and volume of a space 13 formed between the piston 12 and the case 11 is changed by the vibration of a motor vehicle during running so that air in the brake booster 3 is sucked from an air suction port 15 through a pipe 6 having a check valve 7 and is discharged through a pipe 8 having a check valve 9 from an air discharge port 16 so as to generate negative pressure on a brake booster 3 side.