Abstract: A removable folding seat is equipped with a first locking member to lock the front lower portion of a seat frame removably to a floor, a second locking member to lock the rear lower portion of the seat frame removably to the floor, and a third locking member to hold the seat in a folding position. The first and third locking members are simultaneously driven by a first lever. The second and third locking members are driven by the common second lever. When the seat is in a seating position, the second lever is allowed to drive the second locking member and inhibited from driving the third locking member. Also, when the seat is in the folding position, the second lever is inhibited from driving the second locking member and allowed to drive the third locking member.