A keyboard apparatus is provided with a key unit that has a plurality of
keys supported for pivotal motion. Also provided is a detection section
for detecting a key speed when any of the keys are pivoted. The key unit
and detection section are supported by a housing having a bottom member
formed of a resin. A reinforcing member having a sufficient rigidity is
provided to reinforce the bottom member of the housing such as to reduce
warping of the bottom member so as to reduce movement of the detection
section as a result of warping of the bottom member.