To unify the combined products of a resistor and a thermal fuse as well as miniaturize, save resources, and improve functions in a resistance thermal fuse for detecting abnormal heating of an electric heating blanket, an electric carpet, and an electric lap robe or the like by a current value and shutting off the electric circuit.

A resistor 2 is formed by baking a resistance paint on the surface of an insulating case 1. This resistor 2 is connected in series between a lead wire 1a and 1b through a cap 16b and a temperature sensitive element 3. Both lead wires 1a and 1b are installed in a power supply circuit in the electric heating blanket or the like, when a higher current flows than required value because of abnormality, the temperature sensitive element 3 is melted by means of the heat generation of the resistor 2, thereby the circuit is shut off.