PURPOSE: To prevent the slip of the hips in such a state that a backrest part is inclined by providing a reclining seat with a seat part lift mechanism raising the leading end part of a seat part corresponding to the gradual tilting of the backrest part and lowering the same when the backrest part is tilted by a predetermined angle or more.

CONSTITUTION: A seat part lift mechanism 5 is provided with a shaking lever 51 freely revolving around a shaft Q6 and a cam 52 raising and lowering a seat part 1 accompanied by the shaking thereof on a base stand 7. A pair of shaking levers 51 are placed on this side and a deep side and the shaft Q7 attached to the left end part of a slide rod 42 is engaged with the slot 51a formed to the lower end part of the lever 51 in a freely revolvable and shakable manner. When a backrest part 2 is tilted within a predetermined angle range from an erected state, the seat part 1 is revolved clockwise centering around a shaft Q1 corresponding to the tilting angle thereof to be raised on its leading end side. When the backrest part 2 is tilted by a predetermined angle or more, the seat part 1 is reversed centering around the shaft Q1 corresponding to the tilting angle thereof.