To miniaturize an electromagnetic pump by integrally forming a support shaft with a shaft, making the axes of a bearing and the support shaft coincide with each other, preventing loosening of the support shaft caused by a reciprocating motion of a vibrator, and making the outside diameter of the support shaft smaller than the root diameter of an external thread formed on the shaft, and reducing the size of the bearing.

In this electromagnetic pump, en external thread 54 is formed near the end of a frame body 51 of a vibrator 50 of a shaft 53 provided on the vibrator 50, and the tip side from a part formed with the external thread 54 thereon is formed as a support shaft 55 having a diameter smaller than the root diameter of the external thread 54. A fixed plate 63 (a fixed member) attachached with a diaphragm 60 near the end of the frame body 51 of the shaft 53 is attached by screwing a nut 82 to the external threads 54, and the support shaft 55 is supported on a bearing 23a provided on a main body case 10. Therefore, the axes of the bearing 23a and the support shaft 55 coincide with each other. Moreover, the material cost can be reduced by decreasing the outside diameter of the shaft 53.