Plastic parts connected to a plastic fuel tank

The present invention is directed to a plastic part (1) connected to an opening portion (24) of a plastic fuel tank (20). The plastic part (1) includes a body member (30) made of barrier plastic material for preventing the fuel from permeating through the body member (30), and a connecting member (40) made of adhesive plastic material for covering at least a portion of the body member (30) and surrounding the opening portion (24) of the fuel tank (20). The connecting member (40) is formed integrally with the body member (30). The connecting member (40) is connected to the fuel tank (20), with the body member (30) pressed to contact the fuel tank (20) around the opening portion (24). The connecting member (40) has a protrusion (46) formed on a surface of the connecting member (40) connected to the body member (30). As for the protrusion, a step may be formed on an inner side surface of the connecting member (40).