PURPOSE: To obtain a compact and highly efficient moving magnet type transducer by winding a coil on a magnetic core having a magnetic void and connecting a diaphragm to a movable magnet having magnetic pole parts which are mutually reverse polarities holding the magnetic core therebetween and to which the magnetization of the reverse polarity makes the magnetic void a boundary.

CONSTITUTION: A voice current flows to the coil 1 wound on the magnetic core 3 having the magnetic void 2 in a magnetic path, thereby, a virtual electromagnet is formed on the magnetic void part 2. Then, the movable magnet 4 disposed in the vicinity of the magnetic void 2 is driven according to attractive and repulsive force with the electromagnet, the diaphragm 5 connected to the movable magnet 4 is oscillated according to the voice current and operates as an electro-acoustic transducer. On the contrary the movable magnet 4 is oscillated in the vicinity of the magnetic void 2 together with the diaphragm 5, thereby, an acoustic-electrotransducing operation for taking out an electric signal according to the change of a sound pressure is executed in the coil 1. Thereby, a compact size or a low cost is attained and the high efficiency and a long life can be attained.