To provide a blade holder adapted for supporting the blade of a cutter used in opening an envelope, or the like, while eliminating the need for the process of burying it in a cutter body or clamping it against the body during its manufacturing process, and allowing the blade to be easily replaced if edges are worn or chipped.

This blade holder for the cutter allows the blade 3 to fit into a synthetic resin A1 wherein a recess 4 matching the outer shape and thickness of the blade 3 is formed, and a synthetic resin B2 having the same shape as the synthetic resin A1 and having a flat cross section is intimately contacted with the synthetic resin A1 to support the blade 3. The lower part of the synthetic resin B2 intimately contacted with the synthetic resin A1 is molded into a projecting shape 5, which fits into a hole 7 in the cutter body 6.