Pressure vessel

A pressure vessel comprising:

• a cylindrical straight body section, and dome sections which are provided at both ends of the straight body section and narrow as distance from the straight body section increases,
• wherein:
• the straight body section and the dome sections are composed of a resin main body, and an outer shell formed of a fiber reinforced resin material comprising a reinforcing fiber and a matrix resin, the outer shell being provided on the outside of the resin main body;
• each dome section of the main body has pinch-off regions extending from a tip of the dome section toward the straight body section;
• and
• when a distance from the tip of each of the dome sections to a boundary between the straight body section of the main body and each of the dome sections in an axial direction of the straight body section is assumed to be 1,
• an end of each of the pinch-off regions opposite to the tip of the dome section is located in a region where a distance from the tip of the dome section in the axial direction of the straight body section is less than 1;
• in each of the pinch-off regions, a pinch-off line is formed between two thick portions, each of which is a ridge protruding in an arc shape toward the inside of the main body;
• and
• a condition (1) below is satisfied:
• 8×dAF≥dFD, and 8×dAG≥dGE (1),
• wherein A, B, C, D, E, F and G are points on an inner edge of a cross-section obtained by cutting the pinch-off region in a thickness direction, wherein A is a point where the pinch-off line is located, B is a point corresponding to a portion having a maximum thickness in one of the two thick portions, C is a point corresponding to a portion having a maximum thickness in another one of the two thick portions, D is a point closest to the point B among points which are opposite to the point A across the point B and have the same thickness as the point A, E is a point closest to the point C among points which are opposite to the point A across the point C and have the same thickness as the point A, F is an intersection between a curve p passing through the points A and D and a normal line q with respect to the curve p passing through the point B, and G is an intersection between a curve r passing through the points A and E and a normal line s with respect to the curve r passing through the point C,
• dAF is a distance (mm) between the point A and the point F,
• dFD is a distance (mm) between the point F and the point D,
• dAG is a distance (mm) between the point A and the point G, and
• dGE is a distance (mm) between the point G and the point E.