Patent ID: 8277731

Claim:
A sensing device which includes a piezoelectric resonator on whose surface an adsorption layer for adsorbing a substance to be sensed is formed and whose natural frequency changes when the substance to be sensed is adsorbed, and senses the substance to be sensed based on the natural frequency of the piezoelectric resonator, the sensing device comprising: an oscillator circuit oscillating the piezoelectric resonator; an intense excitation circuit intensely exciting the exciting the piezoelectric resonator connected to the oscillator circuit for a preset time period of time by supplying the piezoelectric resonator with high power equal to or more than twice regular power supplied at the time of the measurement of the substance to be sensed, to stabilize the oscillation of the piezoelectric resonator and a connection detecting part that detects the connection of the piezoelectric resonator to the oscillator circuit, and outputs a signal causing the intense excitation circuit to start an intense excitation operation.