To facilitate assembling work at a work site etc., to enhance connection strength between frame bars and rigidity of the whole frame device, and to improve appearance.

The frame unit is provided with: the plurality of frame bars separated from each other and arranged in parallel with each other; and a pair of connection frame bodies provided at both ends of the plurality of frame bars. The pair of connection frame bodies are connected and fixed to the end parts of the respective frame bars by fastening tools such as bolts, and between the frame bar connection parts of the connection frame bodies, fitting hole parts for jointing the connection frame bodies to connection frame bodies of the other frame unit by fastening tools such as bolts and nuts, are provided.