A speaker includes a magnetic circuit 1 that is formed in the center of a frame 5, a voice coil 6 that is inserted in a magnetic gap of the magnetic circuit 1, a damper 7 that is fixed to the frame 5 and the voice coil 6, and a vibrating plate 8 that is fixed to the frame 5 and the voice coil 6. An opening 10 is provided in a bobbin 12 of the voice coil 6. The area of the opening 10 is 0.3% or less of the radial cross-sectional area of the bobbin 12 of the voice coil 6.