Seat lifter structure and vehicle seat equipped with the same

A vehicle seat mounted on a vehicle and having a cushion seat and a seat back, the vehicle seat comprising:

• a seat lifter structure to be raised or lowered with respect to a movable rail supported on a fixed rail fixed to a floor of said vehicle, said seat lifter structure comprising:
• a sector rotatably supported by said movable rail, said sector being arranged facing with said side frame by being pinched and fixed by a pair of flange expanded portions formed on a tubular shaft member rotatably supported by said side frame, and said sector rotating around an axial line of said tubular shaft member along said side frame when said side frame is raised and lowered;
• a ring-shaped spacer having a first ring-shaped abutting surface facing with said sector and said ring-shaped abutting surface having a first outer diameter, and a second ring-shaped abutting surface facing with said side frame and said second ring-shaped abutting surface having a second outer diameter different from said first outer diameter, said ring-shaped spacer being installed in a first orientation between said sector and said side frame with an axial line of said tubular shaft member as a central axis;
• and
• a biasing member biasing and abutting said sector to said first abutting surface and biasing and abutting said side frame to said second abutting surface by biasing said sector and said side frame in a direction of approaching.