A plug-in connector part for connection to a mating plug-in connector part includes: a housing part; at least one electrical contact element, which is arranged on the housing part, for establishing electrical contact with the mating plug-in connector part; and a temperature-monitoring device including at least one sensor device for detecting a rise in temperature of the at least one contact element. The temperature-monitoring device includes a support element that extends over an entire surface thereof along a plane and includes at least one opening and one contact surface arranged at the at least one opening, the at least one contact element extending through the at least one opening such that the at least one contact element abuts the contact surface, and the at least one sensor device being arranged on the support element so as to detect a rise in temperature of the at least one contact element.