An excessive amount of pressurized air is inhibited from being blown to an eye of a patient during measurement of a corneal shape deformation amount. In a non-contact tonometer having a piston, a driving unit to drive the piston, a fluid election unit to blow air pressurized by driving the piston toward a cornea of an eye to be inspected, and an interocular pressure measuring unit to detect a deformed state of the cornea and measure an interocular pressure, there are provided a piston displacement restricting unit that restricts a displacement amount when the piston pressurizes the air, and a changing unit to change the displacement amount to be restricted by the piston displacement restricting unit.
