Method for manufacturing slide fastener

A method for manufacturing a slide fastener comprising:

• a pair of fastener tapes;
• a pair of fastener element rows provided on respective opposing tape-side edges of the pair of fastener tapes, the pair of fastener element rows having a plurality of fastener elements;
• and a slider configured to engage and disengage the pair of fastener element rows with and from each other, wherein each of the pair of fastener element rows is comprised of a monofilament which is made of synthetic resin, the method comprising:
• a step of forming the monofilament by extrusion molding, the monofilament having a surface layer on a surface thereof, the surface layer being able to be colored with dyes;
• a step of forming a roughened surface having a number of concaves on the surface of the monofilament by performing blast processing on the surface of the monofilament;
• a step of shaping the monofilament into the fastener element row;
• and
• a step of dying the fastener element row,
• wherein the surface layer has a thickness ranging from 10 μm to 30 μm, and
• an average roughness degree of the roughened surface is less than a thickness of the surface layer.