Provided is a seat frame for a vehicle seat capable of supporting the back of a seated person during a rear-end collision by using a simple structure and few component portions. The seat frame includes a top frame portion on the top of the seat, lateral frame portions on the right and left of the seat, and a connection frame connecting the tops of the lateral frame portions to bridge them. The connection frame includes a bent protrusion portion bent in the longitudinal direction and arranged in a standing condition from a surface formed by the connection frame, at a position between a pair of the lateral frame portions. The bent protrusion portion is provided over the entire length of the up and down direction of the connection frame.