METHOD FOR MANUFACTURING AIR BAG, AIR BAG, AND VEHICLE SEAT APPARATUS

A method for manufacturing an air bag includes forming a bag portion surrounded by a welded portion extending in an annular shape by pressing at least one welding mold against two sheet materials arranged to be stacked from a stacking direction of the sheet materials. The welding mold is pressed against the sheet materials to form the welded portion including a welding bead portion protruding to an inside of the bag portion between the sheet materials. A pressing surface of the welding mold against the sheet materials is provided with a slope portion facing in the stacking direction of the sheet materials and in a direction of the inside of the bag portion at a position further on an outside of the bag portion than a position at which the welding bead portion is formed.