PURPOSE: To provide a slide unit having the structure in which machining of tap holes adjusted to bolt holes of guide rails are not required and the guide rails can be installed even when their bolt holes' positions differ in the longitudinal direction, when the guide rails for guiding a slider are installed on both right and left side walls.

CONSTITUTION: T-shaped grooves 26 are formed along the overall length in the longitudinal direction on upper faces of both right and left side walls 23 of a guide flame 22 with the U-shaped cross section, and guide rails 29 are installed on attaching faces 25 of the side walls 23 and are attached integratedly to the T-shaped grooves with clamping devices 27 for T-shaped groove consisting of square nuts 27a, which can be inserted in the T-shaped grooves 26, and attaching bolts 27b.