To safely manufacture a thermo-protector of a case type, operated by releasing elastic strain energy of an elastic body held by joining and fixing by a fusible material, by the fusion of the fusible material, safely by eliminating thermal effect when casing.

One end of a linear or plate-shaped elastic body 3 is fixed to one conductor 2 of a pair of conductors 2 and 20 arranged with a predetermined vertical space in a housing 1 by a fusible material 4, the other end of the elastic body 3 is pushed in the longitudinal direction by a pressing piece 5 to elastically bend and deform elastic body 2, and the bent elastic body is contacted with the other conductor 20 to form a contact.