A damper and a speaker apparatus includes the damper, which suppresses damage to an oscillatory system from an excessive input signal, enabling an efficiency increase of the speaker apparatus. As a damper has a planar surface, undue deformation of the oscillatory system due to an excessive input signal is suppressed, and damage to the oscillatory system can be suppressed. Furthermore, since the deformation of a corrugation portion by a normal input signal is hardly prevented, a reduction in sound pressure of the speaker apparatus with respect to an input signal is suppressed, enabling an increase in efficiency. Furthermore, the planar surface is extended at a height in a thickness direction different from that of an attachment portion. Thus, rising portions are deformed when a voice coil bobbin is oscillated, enabling suppression of rupture of the damper in the vicinity of a boundary between the planar surface and the attachment portion.