Patent ID: 8413379

Claim:
A step unit comprising: a step member that is provided on a vehicle main body to be adjacent to a vehicle sliding door, the step member having, on a lower surface thereof, a pair of lower rails extending in an opening-closing direction of the sliding door; and a rail plate member arranged at a cutout portion, which is formed in a part of one of the lower rails, the rail plate member making the lower rail continuous in the opening-closing direction, wherein rollers are coupled to the sliding door and arranged between the pair of lower rails, the rollers, together with the sliding door, being guided by the lower rails in the opening-closing direction, the step member is molded of a plastic material and has an insertion slit and a support extension, the insertion slit extending through the step member in the vertical direction at a position that corresponds to the cutout portion, and the support extension extending from an end of the cutout portion of the lower rail to support the rail plate member against load applied to the rail plate member by the rollers, and the rail plate member is assembled to the step member by being inserted through the insertion slit from above the step member.