A stencil printing apparatus is provided, which comprises a pressure chamber the wall of which is partly constituted by a flexible sheet member, a mount which is disposed in the pressure chamber opposite to the flexible sheet member and on which an article to be printed is placed, a frame for supporting a stencil between the flexible sheet member and the mount, and a pump for reducing pressure in the pressure chamber, in which the pump for reducing pressure is an air pump which comprises a cylinder connected to the pressure chamber and a piston slidably disposed in the cylinder. Stencil printing can be quickly and readily effect by pressure reduction in the pressure chamber. The printing apparatus can be small-sized, lightweight and simplified as a whole, and is improved in operatability.