It is an object of the invention to provide an improved speaker apparatus which maintains the advantages as an inverted dome speaker and has a good directivity and a thin thickness, as well as a broad playback frequency band extending from a high frequency band to a low frequency band. The speaker apparatus includes a dome diaphragm carrying a voice coil and having a concave cross section protruding towards the voice coil, an edge provided on the outer periphery of the dome diaphragm, having a concave cross section protruding towards the voice coil, and supporting the dome diaphragm on a frame, and a magnetic circuit forming a magnetic gap containing the voice coil. Particularly, the edge has a broad edge width {b=(1.5-3)a} bearing a lower playback frequency band than a playback frequency band born by the dome diaphragm.