Generation of warp attributable to expansion and contraction of a light transmissive layer caused by a steep temperature change in an optical recording medium having a relatively thick light transmissive layer is inspected in a short time. The optical recording medium 10 has a reflecting film 16, a recording layer 20 and the light transmissive layer 24 formed of a resin of about 100 mum thick on the polycarbonate supporting base body 12. This optical recording medium 10 is maintained in the atmosphere of 60-80°C for at least 60 minutes, and taken out to a room-temperature environment to measure the change in warp within 60 minutes.
