Seatback frame for vehicle seat

(57) A summary and subject In the seat back frame in the sheet for vehicles equipped with the three-point seat belt, the firm rigidity which compression buckling and modification do not produce is secured in the cases, such as back 突. A weight saving is advanced and application of an active type headrest is enabled. Solution means It is welded to the tube frame 30 in alignment with the seat back's 12 outside, and the tube frame 30, and the seat back frame 30 consists of the seat back's 12 tower frames 50 which maintain the rigidity of a side part on the other hand. The tower frame 50 is formed from the outer side side bracket 51, the inner side side bracket 52, and the insertion brace 53. Effective rigid intensity is secured to the bending load which meets in the direction of vehicles order in the cases, such as back 突, by really forming a flange 511, 521 along the front edge of both the side brackets 51 and 52.