To provide a compact vehicle seat having an impact reducing device, the seat which can be easily mounted on an existing vehicle seat without requiring complicated mechanism or system, and is configured to properly hold an occupant backward in consideration of the figure of the occupant.

When a vehicle seat Z detects an impact force to be applied from the front of a vehicle, a vehicle rear side of a seat position member is displaced in a downward direction relative to the vehicle front side. The vehicle seat Z includes an impact reducing device M having releasing mechanisms 31, 32. When impact force is detected, the releasing mechanisms 31, 32 are released to release support of the impact reducing device M, and a fixed position side of a distance varying member 32 is displaced downward by an occupant's own weight.