A high-pressure tank comprising: a container main body constituted of a body and dome portions disposed on both ends of the body; and a reinforcing layer formed such that a fiber member is wound around an outer periphery of the container main body, wherein the reinforcing layer includes: a hoop winding layer formed by hoop winding that winds the fiber member such that a winding angle (θ) is perpendicular to a central axis of the body; and a high helical winding layer formed by high helical winding of which winding angle (θ) is inclined with respect to the central axis compared with the hoop winding, wherein winding of the fiber member is folded back at the dome portion after the fiber member has made at least a circuit of the central axis at the body, so that the high helical winding layer extends to a dome portion, characterized in that the high helical winding layer includes a thick portion, the thick portion having a thickness (tb) at an outer side of a boundary position between the body and the dome portion with respect to a direction of the central axis, the thickness (tb) being thicker than a thickness (ta) at a part positioned on the body, the hoop winding layer is formed from the body to the dome portion where the thick portion is formed, as a layer at an outer diameter side of the high helical winding layer, and the thick portion of the high helical winding layer has an outer diameter set to equal to an outer diameter of the high helical winding layer positioned on the body. a container main body constituted of a body and dome portions disposed on both ends of the body; and a reinforcing layer formed such that a fiber member is wound around an outer periphery of the container main body, wherein the reinforcing layer includes: a hoop winding layer formed by hoop winding that winds the fiber member such that a winding angle (θ) is perpendicular to a central axis of the body; and a high helical winding layer formed by high helical winding of which winding angle (θ) is inclined with respect to the central axis compared with the hoop winding, wherein winding of the fiber member is folded back at the dome portion after the fiber member has made at least a circuit of the central axis at the body, so that the high helical winding layer extends to a dome portion, characterized in that a hoop winding layer formed by hoop winding that winds the fiber member such that a winding angle (θ) is perpendicular to a central axis of the body; and a high helical winding layer formed by high helical winding of which winding angle (θ) is inclined with respect to the central axis compared with the hoop winding, wherein winding of the fiber member is folded back at the dome portion after the fiber member has made at least a circuit of the central axis at the body, so that the high helical winding layer extends to a dome portion, characterized in that the high helical winding layer includes a thick portion, the thick portion having a thickness (tb) at an outer side of a boundary position between the body and the dome portion with respect to a direction of the central axis, the thickness (tb) being thicker than a thickness (ta) at a part positioned on the body, the hoop winding layer is formed from the body to the dome portion where the thick portion is formed, as a layer at an outer diameter side of the high helical winding layer, and the thick portion of the high helical winding layer has an outer diameter set to equal to an outer diameter of the high helical winding layer positioned on the body.