A vehicle seat in which the attachment mechanism of a support structure for supporting the back of a person seated is prevented from becoming too large, and a seat frame for said vehicle seat are provided. The seat frame F for the vehicle seat S is provided with side frames (15) which are positioned on the left and right sides of a seat back frame (1) and extend vertically. The side frames (15) are provided with a side unit (15a) which extends along the side part of the seat (S), a back part (15c) which protrudes towards the inside of the seat (S) from the back end of the side part (15a), and support members (20, 22) which are provided spanning between the left and right side frames (15) and receive the seatback load of the person seated. The support members (20, 22) are provided with a linking part for linking to the side frames (15) and are attached to the back part (15c) of the side frames (15) in a state in which the positional relation between the linking parts and the side frames (15) is fixed.