A rivet module is provided to join at least two sheets of base materials in a solid state, the rivet module including: i) a shank portion to be mounted on a reciprocal and rotatable joining tool; ii) a base material friction portion that is integrally connected to the shank portion and drills through the base materials as the joining tool causes the base material friction portion to be rotated while applying pressure to the base materials; and iii) a base material fastening portion that is fixedly fitted to the shank portion, supports the base material friction portion, and is fastened to the base materials through a thread formed on the outer peripheral surface thereof.