A degree of freedom in designing a circuit board to which a speaker is attached is enhanced. The speaker including: a frame with a yoke of a magnetic circuit portion embedded inside a central through hole; a diaphragm having a voice coil inserted in a magnetic circuit of the magnetic circuit portion; a cap having a sound dispersing hole that covers over the diaphragm and the frame; and a terminal electrically connected to the voice coil on a side opposite to the cap of the frame, wherein an insulating body is attached to an exposing portion of the yoke on the side opposite to the cap, a back pressure adjusting hole is provided in the exposing portion with respect to the diaphragm, and the terminals are provided to be retractable in the back pressure adjusting hole.