PURPOSE: To prevent the terminals of an overload protecting device from being damaged at the insertion of a cluster into the conductive pin of each of sealed terminals by integrally covering both a connecting terminal and the overload protecting device with a thermally compressive insulator so as to fix both of them.

CONSTITUTION: Plural conductive pin boles 9a, 9b, 9c are bored through the bottom face of a cluster (connection terminal) 5 in such a manner that the conductive pins 3a, 3b, 3c of sealed terminals can be inserted into the respective holes; both the cluster 5 and an overload protecting device 7 are integrally covered with an insulator 10 formed by a thermally compressive insulating tube. While the overload protecting device 7 is mounted to the cluster 5, the cluster is inserted into each conductive pin and fixed. However, both the cluster 5 and the overload protecting device 7 are integrally covered with the insulator 10 formed by a thermally compressive insulating tube, and so terminals 7a, 7b are prevented from being damaged even when a force is exerted on the overload protecting device 7 at the insertion of the cluster 5 into each conductive pin.