To provide a feeder for a vehicle and an electric seat sliding device for a vehicle which can suppress rattling of a feed screw and a nut by bringing a screwed state thereof into a proper state only through the screwing of the feed screw and nut which come into a strong press-fitted state when screwed.

An electric seat sliding device for a vehicle comprises a lower rail fixed to a floor in a vehicle, an upper rail which is freely slidably disposed in a longitudinal direction with respect to the lower rail and which holds a sheet, a feed screw mounted in the upper rail, a nut mounted in the lower rail and screwed with the feed screw, and a drive device which is mounted in the upper rail and which rotatably drives the feed screw. The rear end 13c of the feed screw 13 is provided with a cutting edge 30 so as to extend a direction crossing the extending direction of a screw thread 13b1.