Part fixing structure to resin-made fuel tank and part fixing method thereto

There are provided a part fixing structure and a part fixing method to a resin-made fuel tank which can firmly fix a part to a tank wall (T) without the need of providing a molding die (6) with a convex portion and a recess. A part fixing method for fixing a tank-associated part to a tank wall (T) of a resin-made fuel tank, the part being formed together with a pair of hook portions (2), the method comprising a step of burying the hook portions (2) in the tank wall (T) in a melted state when the resin-made fuel tank is molded, thereby fixing the part to the tank wall (T) after the tank wall (T) is cooled. In order to cause the resin of the tank wall (T) to flow well, a chevron portion (4) having a pair of first inclined faces (3P) is projectingly provided at the bottom face (1a) of the part between the hook portions (2), and a second inclined face (5) which is inclined in a direction opposite to the buried direction (P) toward the tip of the hook portion (2) is formed at the bottom face (1a) of each hook portion (2).