A seat back frame for automobile includes a first side frame and a second side frame that are arranged apart from each other in a vehicle width direction, an upper frame that connects an upper end portion of the first side frame and an upper end portion of the second side frame, and an upper bracket that is attached to the upper end portion of the first side frame and guides a seat belt. The first side frame is an extruded material extending in a vehicle vertical direction, and has a fixed lower end portion. The first side frame has a closed cross-section portion in a cross-section perpendicular to the vehicle vertical direction. The upper end portion of the first side frame is crushed rearward of a vehicle, and a thickness of the upper end portion in a vehicle front-rear direction is smaller than that of the lower end portion.