Abstract: A main body layer 78 is configured by a layer 75 formed, in a cylindrical shape, from a main part 76 and a complementary part 77. The main part 76 is formed by a main prepreg 70. In a small-diameter part, the main prepreg 70 is wound over the entire circumference in a circumferential direction with both ends of the main prepreg 70 in a widthwise direction overlapping each other, and in a large-diameter part, the main prepreg 70 is wound so that a part of the entire circumference in the circumferential direction remains behind as a winding-shortage part, with both ends of the main prepreg 70 in the widthwise direction separated from each other in the circumferential direction. The complementary part 77 is formed to complement the winding-shortage part by a sub-prepreg 71 having a predetermined shape corresponding to the winding-shortage part.