A loudspeaker system includes a speaker enclosure that includes a plurality of faces which surround so as to have an internal space tightly closed, a cut-away portion that is cut away along a contour of a virtual plane figure surrounded by a line on one face of the speaker enclosure while a part of the contour as a connection portion is left, a sealing member that covers the cut-away portion so as to tightly seal the internal space of the speaker enclosure, and a loudspeaker that is provided on any face of the speaker enclosure. A portion of the face surrounded by the cut-away portion is a diaphragm capable of vibrating due to bending elasticity while a near portion of the connection portion serves as a point of support. The sealing member is attached to the diaphragm and a peripheral portion which includes a portion of the one face surrounding the diaphragm so as to tightly seal the internal space of the speaker enclosure in a state that the diaphragm can vibrate.