A folding seat 1 is provided with a leg 4, the leg having a movable hinge portion 42a at the lower end thereof, the movable hinge portion is pivotally connected to a fixed hinge portion 61 on a vehicle body floor 5 so that the leg can tilt down forward to fold the seat on the vehicle body floor The covering structure for the leg 4 includes a leg cover 7 mounted on the leg to cover the leg front surface and the movable hinge portion, and a hinge cover 8 mounted on the vehicle body floor side to cover the fixed hinge portion. The hinge cover has engagement grooves 82 engaging with a movable hinge covering portion of the leg cover so as to allow pivoting of the movable hinge covering portion. The movable hinge covering portion is provided with an engagement edge 72a on the lateral portion thereof so as to be slidably under the inner periphery side of an inside edge 82a of the engagement groove.