A speaker unit, which can be made thin, includes: a magnetic circuit 61 having a space serving as a magnetic gap G formed inside a cylindrical portion 69; a voice coil 85 arranged in the magnetic gap G; and a diaphragm 51 having a center hole 51a that penetrates a center of the diaphragm, an outer peripheral portion 51b supported on a frame 53, and an inner peripheral portion 51c whose inner peripheral surface is connected to the voice coil 85. The cylindrical portion 69 of the magnetic circuit 61 includes a standing wall 69c formed along a vibration direction A of the diaphragm 51, and a slit 69a. The inner peripheral portion 51c of the diaphragm 51 includes an insert hole (a standing wall receiving portion) 57 in which the standing wall 69c is inserted, and an insert portion 59 which is inserted in the slit 69a.