In a non-contact tonometer, puffing of air unnecessary for measurement of an eye to be inspected after driving of a solenoid is stopped is suppressed. In the non-contact tonometer including a corneal shape change unit configured to change the shape of the cornea by pressurizing and supplying a gas in a cylinder by a piston, and an eye pressure measuring unit configured to measure the eye pressure from the state of the shape change of the cornea, an opening portion configured to be formed in the outer wall of the cylinder and decide the internal volume of the cylinder when pressurizing the gas, and a pressurized gas volume change unit configured to change a position where the opening portion can connect the inside of the cylinder with the outside, and change the internal volume of the cylinder when pressurizing the gas.