PURPOSE: To prevent an impact sound from being generated by allowing a seat face to be gently brought into contact with a backrest section near the storage position when a seated person stands up.

CONSTITUTION: This jumping-up speed control device for a chair seat face is provided with a seat face 4 turnably supported on a chair base 2 by a horizontal shaft 3 near the rear end 5 and excited to jump up on the front end 6 side, a cylinder 7 fixed with a head cover 8 pivotally fitted near the front end 6 of the seat face 4 at the front end, a piston 10 slidably engaged in the cylinder 7, a piston rod 11 pivotally fitted to a pin 13 fixed to the piston 10 at the front end and fixed to the upper position of the horizontal shaft 3 at the rear end, and a hole 22 bored near the front end of the cylinder 7. The jumping-up speed of the seat face 4 is controlled by the pressure state of the air in the cylinder 7.