Abstract: A cutting machine used for cutting elongate plastic materials into granules includes a cutting tool, which consists of a roller-shaped body, several knives, and soft metallic bars; the roller-shaped body has lengthwise extended holding trenches spaced on an outer side, and fitting trenches formed along lateral sides of the holding trenches; each knife has a lengthwise extending fitting trench on a lateral side thereof; the knives are fitted in respective ones of the holding trenches of the roller-shaped body with blades thereof projecting out; the soft metallic bars are fitted in respective ones of the holding trenches of the body and touching the corresponding knives; the soft metallic bars are pressed with such an external force as to change shape and project into the fitting trenches of the body as well as the fitting trenches of the knives, thus securing the knives to the body.