A speaker apparatus including: a first diaphragm; a second diaphragm arranged coaxial with the first diaphragm along a driving direction; a frame having diaphragm supporting portions; and a voice-coil bobbin, wherein outer circumferential portions of the first diaphragm and the second diaphragm are fixed to the diaphragm supporting portions respectively, inner circumferential portions of the first diaphragm and the second diaphragm are connected together and fixed to the voice-coil bobbin so as to make a sealed space between the first diaphragm, the second diaphragm and the frame, and the voice-coil bobbin is supported by springiness of a gas contained in the sealed space.