To provide a test apparatus enabling a precise and reliable chatter test.

In test processing, a loudspeaker built in an electronic musical instrument 30 is caused to output a test sound, and a housing surface detection sensor 17 is two-dimensionally scanned to detect a displacement of a panel surface of the electronic musical instrument 30 at step SA2. This scanning is repeated every time when the frequency of the test sound is changed from a minimum frequency to a maximum frequency. Displacement output Dd of the housing surface detection sensor 17, associated with the frequency of the test sound and two-dimensional scanning positions (X-direction scanning position and Y-direction scanning positions) of the housing surface detection sensor 17 respectively, is obtained as inspection data, and a comparison result between the obtained inspection data and a preset limit data (threshold value) is generated. The quality is determined based on the inspection data between the inspection data and the limit data (threshold value) at step SA3. Therefore, unlike conventional manner, a precise chatter test with high reliability can be made without depending on hearing sensitivity of an inspector.