To provide means for simply forming a frame member in a rectangular frame and means for making it possible to easily realize the heat insulating structure of a coupling bolt in case of mounting the rectangular frame at a heat insulating panel in a port frame used for the port of a refrigerator formed in combination with the panel.

Since the port frame for a refrigerator uses a frame member of an L-shaped section and a resin hollow part formed of a shell and a suitable inner rib, a simple rectangular frame an be used to couple the longitudinal frame (b) to the lateral frame (c) by using an L-shaped coupler 6 engaged with the hollow part. In the case of mounting at a heat insulating panel, it can be easily shut off from the contact with the atmosphere by disposing the head of a coupling bolt or nut at the hollow part.