Described is a feed mechanism for a slider which is convenient to use with good durability and low costs by eliminating a rack-and-pinion method. The feed mechanism allows the slider to be fed and moved along a longitudinal main scale. The feed mechanism includes a driving gear that is a gear train pivotally supported by the slider, a driven roller that meshes with the driving gear and rotates by rotation of the driving gear, and an arm that includes a cup portion capable of receiving the driven roller on a distal end. The arm includes the cup portion capable of receiving the driven roller on the distal end and is pivotally supported by the slider on a base end. The cup portion in a state of receiving the driven roller is biased toward the main scale by a pin plunger. Accordingly, the driven roller is kept abutted against the main scale.