A non-contact ultrasonic tonometer for measuring intraocular pressure of an examinees eye in non-contact manner by use of an ultrasonic wave comprises: a probe including a vibrator for making the ultrasonic wave incident on the eye and a sensor for detecting the ultrasonic wave reflected from the eye a detection unit which detects an alignment state of the probe with respect to the eye a determination unit which determines whether the alignment state is proper or not based on a detection result of the detection unit a trigger signal generation unit which generates a trigger signal to start measurement based on a determination result of the determination unit and a control unit which controls the probe to emit the ultrasonic wave based on generation of the trigger signal.
