Patent attributes
A seat sliding device includes a lower rail, an upper rail, a lever member, a lock member, a biasing member and an operation member. The upper rail includes a shaft member, and the lever member includes bearings engaging with the shaft member. Each of the left and right bearings has a surface in contact with the shaft member at one point in an up-down direction by being biased by the biasing member. In the pair of left and right bearings, a surface in contact with the shaft member in one bearing is formed as an arc-shaped surface with a radius slightly larger than an outer diameter of the shaft member, and a surface in contact with the shaft member in the other bearing is formed as a flat surface extending relative to the upper rail in the longitudinal direction.