To provide a rod holder that hardly falls off using the same technology as that of a joint fitting of an iron pipe for a scaffold.

In a single pipe joint fitting of a structure composed of a gear box 1, which is a body part, four clamping plates 2, two friction elements 3, and one main shaft 4, when a fastening screw 5 is turned, the main shaft rotates and the friction elements 3 move toward a central direction so that the clamping plates 2 are pushed and extended, and the single pipe joint fitting is fixed inside a pipe firmly. Also, by cutting a fall-off preventing groove 6 in the clamping plates 2, the friction with the pipe becomes large, and the single pipe joint fitting hardly falls off. Concerning a rod holder, its body is attached to one side of the single pipe joint fitting.