To provide the shoe assembly of a film lapping device for automatically and continuously flowing together two kind workpieces different in diameters through stepless replacement, and eliminating a step replacing time.

A pair of shoe assemblies 30 has at least a pair of small diameter stones 31 having a small diameter circular arc surface conforming to a small diameter circular arc in the inside, and at least two pairs of large diameter stones 32 having a large diameter circular arc surface conforming to a large diameter circular arc arranged in the outer side of the stones 31. Since the assemblies 30 are automatically aligned, two kind shafts 34 and 35 to be worked, can be automatically and continuously worked in stepless replacement by using a diameter-adaptable two-step curvature shoe.