PURPOSE: To visually recognize metal plastic deformation generated after riveting by marking regulative line on the surface of a rivet before being used, carry out riveting on a material to be joined, taking out the rivet by breaking the material to be joined and observing deformation which appears on a marked line.

CONSTITUTION: A line is marked on the axis part 1a and the head part 1b of a rivet 1 before riveting. The line is marked at a prescribed pitch space in the circumferential direction of the axis part 1a and the head part 1b, and at a prescribed angle in center axis direction including the head part 1b. The rivet 1 is inserted in the penetrating hole 2a of double laminated joined member 2, the axis part 1a is riveted by a riveter so as to be generated plastic deformation on the axis part 1a, and the joined material 2 is joined with the rivet 1. In this condition, the joined material 2 is broken, and it separates from the rivet 1, deformation of making line on the surface of the rivet 1 is observed, and plastic deformation which is generated after the rivet 1 is riveted is recognized by eyes, so that a material size can be restricted to the minimum.