PURPOSE: To prevent the support member from becoming unsightly by being pushed up by means of the piping after fixing the support member in such a way that clips to grip the piping is integrally provided on the lower side of the floor trim support member.

CONSTITUTION: Plural clips 4b for gripping the piping T which passes through the space S that is surrounded by a floor trim support member 4, a floor panel 2, and an inner panel 3a of a side sill 3 are integrally installed on the lower side at the center part of the floor trim support member 4. Since the clips 4b are arciformly made at their sections, and the piping T can be gripped by means of elasticity, there is no instance such that the floor trim support member 4 is pushed up by the piping T.