An underwater cutting pelletizer is disclosed wherein a water chamber is circular in plan, an inlet portion is formed on one side in a diametrical direction of the water chamber to introduce cooling water into the water chamber, and an outlet portion is formed on the other side in the diametrical direction of the water chamber to discharge the cooling water from the interior of the water chamber to the exterior, the inlet portion being in a divergent shape in an inflow direction of cooling water. The retention time of pellets in the interior of the water chamber can be made as short as possible.
