Fiber structure

A fiber structure, comprising:

• a liner that includes:
• a cylindrical body portion;
• a dome portion that is continuous with the body portion in an axial direction in which a central axis of the body portion extends, the dome portion having a shape tapering toward the central axis;
• and
• a shoulder portion that is a part of the dome portion and is an area adjacent to the body portion;
• and
• a fiber-reinforced base member covering the liner from outside, wherein
• the fiber-reinforced base member includes:
• first yarns arranged such that yarn main axes of the first yarns extend in the axial direction;
• and
• second yarns arranged such that yarn main axes of the second yarns extend in a circumferential direction of the liner,
• the fiber-reinforced base member includes:
• a first section extending between the shoulder portion and the body portion so as to cover at least a boundary between the body portion and the dome portion;
• and
• a second section that is a section excluding the first section, and
• an average degree of interlacing between the first yarns and the second yarns is lower in the first section than in the second section.