Abstract: A back-rest frame of a vehicular seat comprises a generally U-shaped frame member. The frame member includes a generally U-shaped upper section with which a pair of side sections are integrally connected. The frame member is formed of an elongate material which is made of an aluminum light alloy and has the same sectional shape throughout the length thereof. The elongate material includes a hollow base section with which extended wall sections are integral. The frame member is produced by bending the elongate material into a generally U-shape and then by cutting off the extended wall sections from a part corresponding to the upper section of the frame member.