A high-pressure gas storage container (1, 2) comprising: a liner for housing high-pressure gas; and a reinforcing layer that is formed by winding strip-shaped reinforcing members around an outer perimeter surface of the liner, wherein: the reinforcing members are made of reinforcing fibers that are impregnated with resin; the liner comprises a body portion having in a center with a tubular shape extending in an axial direction, a pair of mirror portions provided on both sides of the body portion in the axial direction and that are curved so as to taper toward the outer sides in the axial direction, and shoulder portions that are provided at boundaries between an inner perimeter surface of the body portion and inner perimeter surfaces of the mirror portions; the reinforcing layer includes a hoop layer formed by winding the reinforcing member around the body portion along the circumferential direction, and a helical layer (32, 320) formed by winding the reinforcing member around the body portion and the mirror portions in a spiral shape, characterized in that at least a portion of the reinforcing fibers that constitute the reinforcing member wound in the helical layer has an acidic functional group which has been added by irradiating plasma on the reinforcing fibers. a liner for housing high-pressure gas; and a reinforcing layer that is formed by winding strip-shaped reinforcing members around an outer perimeter surface of the liner, wherein: the reinforcing members are made of reinforcing fibers that are impregnated with resin; the liner comprises a body portion having in a center with a tubular shape extending in an axial direction, a pair of mirror portions provided on both sides of the body portion in the axial direction and that are curved so as to taper toward the outer sides in the axial direction, and shoulder portions that are provided at boundaries between an inner perimeter surface of the body portion and inner perimeter surfaces of the mirror portions; the reinforcing layer includes a hoop layer formed by winding the reinforcing member around the body portion along the circumferential direction, and a helical layer (32, 320) formed by winding the reinforcing member around the body portion and the mirror portions in a spiral shape, characterized in that at least a portion of the reinforcing fibers that constitute the reinforcing member wound in the helical layer has an acidic functional group which has been added by irradiating plasma on the reinforcing fibers. the reinforcing members are made of reinforcing fibers that are impregnated with resin; the liner comprises a body portion having in a center with a tubular shape extending in an axial direction, a pair of mirror portions provided on both sides of the body portion in the axial direction and that are curved so as to taper toward the outer sides in the axial direction, and shoulder portions that are provided at boundaries between an inner perimeter surface of the body portion and inner perimeter surfaces of the mirror portions; a body portion having in a center with a tubular shape extending in an axial direction, a pair of mirror portions provided on both sides of the body portion in the axial direction and that are curved so as to taper toward the outer sides in the axial direction, and shoulder portions that are provided at boundaries between an inner perimeter surface of the body portion and inner perimeter surfaces of the mirror portions; the reinforcing layer includes a hoop layer formed by winding the reinforcing member around the body portion along the circumferential direction, and a helical layer (32, 320) formed by winding the reinforcing member around the body portion and the mirror portions in a spiral shape, a hoop layer formed by winding the reinforcing member around the body portion along the circumferential direction, and a helical layer (32, 320) formed by winding the reinforcing member around the body portion and the mirror portions in a spiral shape, characterized in that at least a portion of the reinforcing fibers that constitute the reinforcing member wound in the helical layer has an acidic functional group which has been added by irradiating plasma on the reinforcing fibers.