A warpage angle measurement apparatus and a warpage angle measurement method are provided that can measure an angle of warpage of an optical disc and a cartridge for the optical disc caused by a rapid environmental change such as a temperature change or a humidity change in a short time. The warpage angle measurement apparatus 10 includes: a constant temperature chamber 22 for accommodating an optical recording medium 20 formed by mounting the optical disc 16 as an object to be measured in the cartridge 18 and for adjusting a surrounding of the optical recording medium 20 to have a predetermined environmental condition; a laser oscillator 24 for causing laser oscillation to emit laser light to the optical disc 16; and a light-receiving unit 26 for receiving the laser light reflected from the optical disc 16 and detecting a relative angle of an optical path L2 of the reflected laser light with respect to an optical path L1 of the emitted laser light.