Temperature management member under reduced-pressure atmosphere and temperature management method under reduced-pressure atmosphere

A temperature management method under a reduced-pressure atmosphere comprising steps of:

• making a temperature-sensitive discoloration layer containing a granular or powdery hot-melt matter that melts at a melting temperature corresponding to a heating temperature to be detected under a reduced pressure;
• adjusting a difference in a melting temperature of the hot-melt matter in the temperature-sensitive discoloration layer, between under an atmospheric pressure atmosphere and under a reduced-pressure atmosphere, to be 5° C. at most thereby;
• preparing the temperature management member under the reduced-pressure atmosphere by arranging a temperature-sensitive discoloration layer which discolors in response to the hot melting, on a substrate thereby;
• heating the temperature management member together with the object to be heated at the time of heating the object to be heated under a reduced-pressure atmosphere;
• and
• managing a history that shows whether or not the heating temperature to heat the object to be heated reaches at a temperature to be detected, by checking the discoloration of the temperature-sensitive discoloration layer of the temperature management member.