A refrigerant processing device includes a main body, and a pipe and a narrow tube that feed a refrigerant into and out of the main body. The main body has a cylindrical body part, and upper and lower end wall parts that close both ends of the cylindrical body part. The pipe passes through the lower end wall part, and extends along a central axis of the cylindrical body part. The narrow tube passes through the upper end wall part. A first spiral groove extending in a spiral shape with respect to the central axis is formed on an inner circumferential surface of the cylindrical body part. A second spiral groove extending in a spiral shape with respect to the central axis and a linear groove extending in a direction of the central axis are formed on an outer circumferential surface of the pipe.