The present invention comprises a fluid-injectable internal bag layer, a base-material layer superposed on an external periphery of the internal bag layer and impregnated with a photo-curing resin, and an outer layer superposed on an external periphery of the base-material layer and having transparency. The base-material layer is formed of a composite member serving as a reinforcing fiber layer impregnated with the photo-curing resin, and a grid net superposed on the composite member and preventing flow of the photo-curing resin.