SENSOR DEVICE FOR DETECTING DISPLACEMENTS OF HUMAN'S BODY SURFACE ACCOMPANYING RESPIRATION

In a sensor device which detects pressure variations owing to displacements of a body surface of a subject by respiration through variations of the output impedance of a piezoelectric vibrator, the pressure variations can be more efficiently transmitted to the piezoelectric vibrator. The sensor device, attached to a subject's body surface, comprises a contact piece contacting the body surface; a displacement-signal convertor which converts the displacements of the body surface into electrical signals; and an outputting device which outputs the electrical signals to an external unit; the sensor device is clamped between the body surface of the subject and an upper edge portion of a subject's bottom garment, and the contact piece is arranged in one side surface of a housing, and a stopping member which can be attached with the upper edge portion of the bottom garment in the other side surface of the housing.