A joining method for joining together a first member in which fiber material is mixed into a first resin, and a second member that includes at least a second resin, includes abutting the first member and the second member together, and softening or melting the first resin of the first member and the second resin of the second member that are adjacent to abutting surfaces of the first member and the second member; and stirring a joint forming portion formed by the softened or melted first resin of the first member and the softened or melted second resin of the second member, and the fiber material included in the softened or melted first resin of the first member, in a direction inclined with respect to the abutting surfaces, and hardening the joint forming portion.