To make an electromagnetic sounding unit small-sized and lightweight.

A plastic magnet 7 is formed by injection molding with high precision, the gap W1 between a diaphragm 10 and the peak of a magnetic core 4 and the gap W2 between the diaphragm 10 and a coil 6 have their size errors suppressed small, and the diaphragm 10 is supported directly by a diaphragm support surface 11 of the plastic magnet 7. Here, the plastic magnet 7 is molded of a material obtained by mixing ferrite magnetic body powder and rare earth magnet powder with a resin material by injection. The magnetic force of the plastic magnet 7 can properly be adjusted to design conditions of the electromagnetic sounding unit by varying the weight ratio of the ferrite magnetic body powder and rare earth magnet powder.