Abstract: A back-rest frame structure for a vehicular seat comprising a generally U-shaped frame that includes an upper frame section. The upper frame section has a generally channel-shaped section and includes an upper end wall portion formed with through-holes for receiving holders for stays of a head rest. First and second side frame sections are integrally connected respectively to the opposite end portions of the upper frame section. The generally U-shaped frame is produced from a metal sheet as a one-piece structure. A support bracket is fixed to the upper frame section and adapted to support the holders for the head rest stays. The support bracket includes a support section for supporting the holders, located opposite to the upper end wall portion of the upper frame section of the frame. The support section is formed with through-holes facing those of the upper end wall portion of the upper frame section so as to respectively receive the holders.