A loudspeaker apparatus comprises a housing, an adsorptive material provided inside the housing, for physically adsorbing gas inside the housing, a vibration section including a diaphragm and provided in an opening formed in the housing, a drive section for driving the diaphragm to generate sound from the diaphragm, and a negative stiffness generating mechanism provided inside the housing, for reducing an acoustic stiffness inside the housing, the acoustic stiffness acting on the diaphragm.