A baseplate carries on its surface a pad constituting a strike surface and a tubular rim surrounding the pad and constituting a strike ring. A pad sensor is provided on the surface of the baseplate in the central area thereof for detecting the vibration of the baseplate caused by a strike on the pad, and a rim sensor is provided between the rim and the baseplate for detecting the vibration of the rim. The electric signals representing the detected vibrations trigger the generation of tone signals of drum sounds. The baseplate is supported via vibration absorber pieces on a support frame. Thus, disturbing vibrations externally given to the support frame will be prevented from propagating up to the baseplate, being absorbed by the vibration absorber pieces.