To reduce resistance values of an electrode in a lower part of an insulative frame body and to prevent delamination of an insulative substrate with the insulative frame body in a protection device wherein a plurality of electrodes are provided on an isolated position on the insulative substrate, the protection device having the insulative frame body integrally formed on the insulative substrate with the electrodes partly exposed and comprising a soluble alloy contacted and fixed over the exposed electrodes.

In an object that electrodes 2 and 3 are formed on an insulative substrate 1 and that an insulative frame body 4 is integrally laminated, a thickness of the electrode in a lower part of an insulative frame body 4 is set to be 10 to 35 μm. Furthermore, an electrode of a 15 to 50 μm thickness is formed on an insulative substrate green sheet 1 and the insulative frame body 4 is laminated, pressurized and fired. Thereby, effects are taken to provide a protection device wherein the self heat generation caused by greater resistance values of the electrode in the lower part of the insulative frame body 4 can be ignored, mismelt of the soluble alloy is not occurred and the delamination of the insulative substrate with the insulative frame body is not generated.