Linear motion guide unit

The linear motion guide unit has a guide rail, a slider, and a plurality of balls. The slider includes a coil spring disposed in the first circulation path so as to extend in the longitudinal direction. The coil spring includes: a pair of first regions provided at both ends in the longitudinal direction and embedded in the first circulation path; and a second region having a smaller diameter than the pair of first regions, the second region being disposed between the pair of first regions and the inner wall surface of the first circulation path with a gap therebetween. 直动引导单元具有导轨、滑动件、以及复数个滚珠。滑动件在第一循环路内包括以沿长边方向延伸的方式配置的螺旋弹簧。螺旋弹簧包括：一对第一区域，设置于长边方向的两端部，嵌入第一循环路；以及第二区域，直径比一对第一区域的直径小，在一对第一区域之间与第一循环路的内壁面之间隔开间隙地配置。