PURPOSE: To prevent the displacement of the bending engagement part of a metal product by executing a friction adhesion by deforming one part of a bending part or providing a tongue piece at a bending end part and abutting it by bending to the other bending part, in the case of connecting the bending part of a metal plate end part by engaging each other.

CONSTITUTION: The bending parts 6, 12 of the adjacent end part of metal plates 8, 10 are connected by engaging each other. In that case, an L shaped part 13 is deformed and subjected to a friction adhesion to the other bending part 12 to prevent the displacement of a connection part. The displacement of the connection part may be prevented by bending the tongue part 16 provided at the bending part 12 end and abutting it to the other L part 13. With said technique the displacement of the connection engaged part of a metal product 18 is completely prevented.