To provide a tray tester for a heating cart which enables electrical testing of trays each with a resistance heater being incorporated thereinto and trays each with a PTC heater incorporated thereinto at a time with one unit, and moreover achieves a simple and easy realization thereof.
Trays 9, each having a heater 11 incorporated thereinto, are housed into a heating cart in multiple levels so as to freely move in or out. In the testing, the individual trays 9 are taken out to be housed into the tray tester 22. The tray tester 22 has a sequence control part 23 to sequentially select the trays 9 for testing, a resistance measurement part 24 for the heater 11 of the tray 9 to be tested, a comparison judgment part 25 for comparing measured resistance value with another allowable resistance value and a result display part 26 for displaying the results of judgment as to whether the measured resistance value lies within any allowable resistance value.