To issue an alarm at a temperature lower than a defrosting temperature when the temperature in a cooling chamber is increased by abnormal conditions of equipment or the like.

A temperature monitoring system of a showcase 1 includes: a definition data acquisition unit 21 for acquiring definition data including an alarm temperature in the showcase 1; a measurement data acquisition unit 22 for acquiring measurement data including the temperature in the showcase 1, and for detecting whether the defrosting is performed; and an equipment operation unit 23 for issuing the alarm when the defrosting is not performed and the temperature in the showcase 1 exceeds the alarm temperature.