To control a heating sheet portion at a prescribed temperature while simplifying the structure of a connector connecting the heating sheet portion to a controller.

The sheet heating appliance comprises the heating sheet portion 10 in the form of a sheet and incorporating a heater wire 12, and a controller 3 connected to the heating sheet portion 10 through the connector 14. The controller 3 has an environmental temperature sensor 8 provided in the side of the heating sheet portion 10 which is nearer to the controller 3 side than to the connector 14 and detecting an environmental temperature, a control circuit 40 controlling electrical power supplied to the heating sheet portion 10 by an environmental temperature detected by the environmental temperature sensor 8, and a storage portion 41 storing a maximum temperature. The control circuit 40 controls electrical power supplied to the heating sheet portion 10 so as to reduce the power with the approach of the environmental temperature detected in the environmental temperature sensor 8 to the previously stored maximum temperature.