PURPOSE: To form projections more simply and inexpensively in comparison with double injection method, or the like, by applying an ultraviolet-curing or electron ray-curing resin on the surface of a material to be worked, pressing a pierced sheet on the resin to form projections, and curing the projections.

CONSTITUTION: An ultraviolet-curing or electron ray-curing resin is applied on the surface of a material 9 to be treated to form a coating 10. The pierced sheet 12 having a plurality of holes 11 is placed on the coating 10, and pressure is applied to form projections 8. An ultraviolet or electron ray is irradiated over the sheet 12 so as to cure the projections 8. The sheet 12 is removed from the material 9, and the remaining part of the coating 10 is washed off.