To provide a press-fitting device capable of manufacturing a poduct of high quality at the time of press-fitting a press-fitting surface of an inner member on a surface to be press-fitted of a housing by moving a punch in the axial direction concerning the housing on an inner peripheral edge of the surface to be press-fitted of which inner R is formed and the inner member on an outer peripheral edge of the press-fitting surface of which outer R is formed.

A rod 10a of an air cylinder 10 fixes a tsandard surface W1a of a bearing W1 in the horizontal direction. A placing base 3 provided between the rod 10a and a punch 15 places a throttle pulley body W2 free to move by making outer R W1c and inner R W2b with each other in the horizontal direction.