To provide an easily and speedily mountable lighting device capable of easily adjusting a light distribution.

This lighting device includes a lighting device body 2 equipped with a long fluorescent lamp 5, and end caps 3, 3 provided at both end parts of the lighting device body so that they can freely rotate relatively to the lighting device body. An adjusting means to fix the lighting device body and the end caps so that they can be freely released at a prescribed relative position and light distribution of illumination light can be adjusted, and the cross section of the end cap is formed into a non-circular shape so as to have a plurality of faces 30a-30h which can be placed on a mounting surface 40 such as a floor or mounted to faces to be mounted such as a wall and a ceiling in its circumferential direction.