PURPOSE: To eliminate occurrence of distortion and color deviation in a picture even if the front part of the unit and a television picture are adjoined by providing a dust cap formed of magnetic material on the sound producing face side of a diaphragm made of magnetic material.

CONSTITUTION: The unit is composed of a main magnet 1, a lower plate 2, a cancel magnet 3 an upper plate 4, an iron frame 5, an iron cover 6, a voice coil 9, a damper 10, an edge 11 and a cabinet 12, and a diaphragm 13 and a dust cap 14 are made of magnetic material respectively. As a countermeasure against leakage flux is made on the rear face of a dynamic loudspeaker similarly with usual examples, almost no leakage flux occurs. As for the front face part, occurrence of leakage flux is the same with former examples. However, as the diaphragm 13 and dust cap 14 are made of magnetic material, leakage flux pass inside of the diaphragm 13 and dust cap as shown by an arrow mark a, and accordingly, the value of leakage flux to the front of the dynamic loudspeaker decreases remarkably.