Vehicle seat sliding device

A vehicle seat sliding device comprising:

• a lower rail that is fixed to a vehicle floor;
• an upper rail that slidably engages with the lower rail and supports a vehicle seat upward;
• a nut member fixed to a first rail which configures one side of the lower rail and the upper rail;
• a screw rod that is screwed into the nut member;
• a drive unit that rotates the screw rod;
• and
• a support that supports the screw rod on a second rail which configures the other side of the lower rail and the upper rail,
• wherein the support includes
• a holding member that is provided with an insertion hole into which the screw rod is inserted and that is fixed to the second rail, and
• a holding nut that is provided with a through-hole into which the screw rod is inserted and that is screwed to a screwing portion provided on the screw rod or the holding member,
• the holding nut is configured to pinch, in cooperation with a pinch portion provided on one side of the screw rod and the holding member which have the screwing portion, a pinch target portion provided on the other side of the screw rod and the holding member,
• the pinch target portion has a first curved surface that comes into contact with the holding nut in a slidable manner, and a second curved surface that comes into contact with the pinch portion in a slidable manner, and
• the first curved surface and the second curved surface are configured to form a part of spherical surfaces that are concentric with each other.