A non-contact ultrasonic tonometer (100) for measuring intraocular pressure of an examinees eye (E) in non-contact manner by use of an ultrasonic wave comprises: a probe (10) including a vibrator (11) for making the ultrasonic wave incident on the eye and a sensor (13) for detecting the ultrasonic wave reflected from the eye detection means (20, 40, 50, 55, 70) for detecting an alignment state of the probe with respect to the eye determination means for determining whether the alignment state is proper or not based on a detection result of the detection means trigger signal generation means for generating a trigger signal to start measurement based on a determination result of the determination means and control means for controlling the probe to emit the ultrasonic wave based on generation of the trigger signal.
