To prevent a service life from being shortened by a change of material quality or the like due to repeated deformation of components formed of a soft material such as a diaphragm part and a discharge valve by a pumping effect, or to prevent generation of noise or the like caused by adhesion to other components.

Components such as a diaphragm part 11, an intake valve 19, and a discharge valve 13 are formed of a flexible material such as rubber and synthetic rubber, and the shape or the like thereof is changed during a pumping effect. Fine powder formed of a material of excellent adhesivity to the material of the above components is adhered to surfaces of these flexible components.