To provide a Thomson blade cutter that facilitates exchanging a cutting mold so that the shape of a cut face is not collapsed at the cutting of a Thomson blade.

In a device for cutting the Thomson blade in which an upper blade of the cutting mold driven by a handle is vertically displaced with respect to a lower blade of the fixed cutting mold, and placed on the lower blade, the Thomson blade cutter is characterized in that the lower blade of the cutting mold is constituted of a portion in which the lower blade of the cutting mold contacts with the body of the Thomson blade and a portion in which the lower blade contacts with the tip of the Thomson blade, and the portion in which the lower blade contacts with the tip of the Thomson blade can easily be attached to and separated from the portion in which the lower blade contacts with the body of the Thomson blade.