Disclosed is a seat pumping device for a vehicle. The present invention provides a seat pumping device for a vehicle, the seat pumping device including: a clutch device which is rotated clockwise or counterclockwise by receiving external manipulation force, and has one or more manipulation flanges that are disposed at a predetermined interval in a circumferential direction and protrude in an axial direction; and a brake device which has one or more manipulation grooves in which the manipulation flanges are accommodated to come into contact with the manipulation grooves clockwise or counterclockwise so that the brake device is rotated clockwise or counterclockwise by receiving the external manipulation force from the clutch device, and performs a brake function such that the brake device is not rotated clockwise and counterclockwise by external force that is not through the clutch device.