To relieve a load to a motor by a method wherein the spring constant of a leaf spring is reduced so that the leaf spring is prevented from buckling.

A drive shaft 3 eccentrically attached on the output rotary shaft 2 of a motor 1; a working member 5 reciprocated through rotation of the drive shaft 3; and a diaphragm member 7 arranged in a direction crossing the axial direction of the output rotary shaft 2, and a leaf spring 5c having spring properties in a surface paralleling the axial direction of the output shaft 2 of the motor 1 and only in the reciprocating direction of the working member 5 is provided. The leaf spring 5c as one end coupled to the working member 5 and the other end coupled to a case body 6. At least one of one end and the other end described above is rotatably supported in a state to constrain movement in a direction crossing the reciprocating direction of the working member at right angles.