A speaker includes a holder and a vibration unit and a magnetic circuit unit fixed and held at the holder. The vibration unit includes: a first diaphragm and an elastic support located at an end of the voice coil facing away from the first diaphragm and elastically supporting the voice coil. The elastic support includes a flexible circuit board and a second diaphragm fixed and held at one side of the flexible circuit board facing away from the voice coil. The flexible circuit board is sandwiched between the voice coil and the second diaphragm and includes an upper surface fixed to the voice coil and a lower surface opposite to the upper surface. The second diaphragm is fixed to the lower surface by a binder, and the lower surface is recessed towards the upper surface to form a binder accommodation groove.