To provide a parts feeder which automatically peels a part comprising a sheet key switch mounted on a pasteboard at a predetermined pitch longitudinally of the pasteboard and mounts the part at a predetermined position.

An adsorption head 22 is mounted at an air cylinder 21 which is mounted at the movable member 20 of an x-axis unit 19 of a robot and adsorbs a sheet key switch 46 on a pasteboard 47 at a slide base 27, in this state, a discharge roller 37 is driven in the discharging direction. This allows the sheet key switch 46 to be peeled from the pasteboard 47 while backing off the slide base 27 in the reverse direction of feed against the elastic restoring force of an extension coiled spring 31 by means of the tensile force of the pasteboard 47. The air cylinder 21 is mounted at a predetermined position on a substrate 14 by means of the x-axis unit 19 and a y-axis unit 12 thereafter.