PURPOSE: To simplify a work process wherein a lower case is formed of resin to reduce weight and the generation of noise during drive is lowered.

CONSTITUTION: A drive part comprising an electromagnet 1, a permanent magnet 2, and diaphragms 3 and 3' is integrally assembled through a chassis 14. A lower case 10 is formed of resin reinforced with glass fibers and an inorganic filler. A drive part assembled through the chassis 14 is supported through a mount bush 15, formed of rubber, on a bottom plate 11, of which a ventilation chamber 7 in coordination with the lower case 10. In which case, a ratio D/W flexural rigidity D of the bottom plate 11 and the weight W of an oscillation pump is set to 5000(Kgf.mm/kg) or more.