A cutting chamber housing for an underwater pelletizer having an inlet for cooling fluid and an outlet for cooling fluid with pellets. The cutting chamber housing encloses a cutting device having a rotary drive and a cutting head with rotating cutting knives. An extrusion head having a perforated plate projects into the cutting chamber housing. The cutting chamber housing has a stationary upper housing half and a movable lower housing half along a separation plane arranged at an oblique angle so that the cutting chamber housing can be opened at least downwards along the separation plane. Features such as slide rails, swivel joints, or rotary joints can be added to enable easy opening of the cutting chamber housing.