A synthetic resin bottle formed by blow molding including: a mouth through which a content medium is dispensed; a trunk contiguous with and below the mouth; and a bottom that is contiguous with and below the trunk and that is provided with a reduced pressure absorbing region configured to be displaced toward an inside of the bottle in response to reduced pressure inside the bottle, wherein the trunk includes a cylindrical-shaped straight region which has a length of not less than 100 mm in an axis direction extending along a center axis of the trunk and in which no irregularities are provided, the bottom includes a heel portion, which has an upper end opening connected to a lower end opening of the trunk, and a bottom wall portion, which closes a lower end opening of the heel portion and which has an outer circumferential edge portion serving as a ground contacting portion, the bottom wall portion includes a tubular-shaped rising wall, which is contiguous with the inner side of the ground contacting portion in the radial direction and which extends upward, and a reduced pressure absorbing region, which is contiguous with an upper end portion of the rising wall and which is provided on the inner side of the rising wall in the radial direction, the reduced pressure absorbing region includes an annular-shaped outer side wall, which is contiguous with the rising wall via an annular-shaped curved surface portion as a pivot point of rotating displacement and which is convex downward, an inner side wall, which is contiguous with the inner side of the outer side wall in the radial direction and which extends upward, and a ceiling wall, which is located on an upper end of the inner side wall, characterized in that the straight region has a weight of not less than 11 times a weight of the reduced pressure absorbing region, wherein the trunk has an upper region which is contiguous with and above the straight region and which extends to the mouth while being reduced in diameter upward, a lower region which is contiguous with and below the straight region and which extends to the bottom straightly and an annular-shaped groove which is formed between the straight region. and the lower region, wherein the upper region is wider in diameter, where the straight region joins the upper region, than the straight region through a stepped portion formed between the straight region and the upper region, wherein the lower region is the same diameter as the straight region, and wherein the heel portion is wider in diameter, where the heel portion joins the lower region, than the lower region through a stepped portion formed between the heel portion and the lower region. a mouth through which a content medium is dispensed; a trunk contiguous with and below the mouth; and a bottom that is contiguous with and below the trunk and that is provided with a reduced pressure absorbing region configured to be displaced toward an inside of the bottle in response to reduced pressure inside the bottle, wherein the trunk includes a cylindrical-shaped straight region which has a length of not less than 100 mm in an axis direction extending along a center axis of the trunk and in which no irregularities are provided, the bottom includes a heel portion, which has an upper end opening connected to a lower end opening of the trunk, and a bottom wall portion, which closes a lower end opening of the heel portion and which has an outer circumferential edge portion serving as a ground contacting portion, the bottom wall portion includes a tubular-shaped rising wall, which is contiguous with the inner side of the ground contacting portion in the radial direction and which extends upward, and a reduced pressure absorbing region, which is contiguous with an upper end portion of the rising wall and which is provided on the inner side of the rising wall in the radial direction, the reduced pressure absorbing region includes an annular-shaped outer side wall, which is contiguous with the rising wall via an annular-shaped curved surface portion as a pivot point of rotating displacement and which is convex downward, an inner side wall, which is contiguous with the inner side of the outer side wall in the radial direction and which extends upward, and a ceiling wall, which is located on an upper end of the inner side wall, characterized in that the straight region has a weight of not less than 11 times a weight of the reduced pressure absorbing region, wherein the trunk has an upper region which is contiguous with and above the straight region and which extends to the mouth while being reduced in diameter upward, a lower region which is contiguous with and below the straight region and which extends to the bottom straightly and an annular-shaped groove which is formed between the straight region. and the lower region, wherein the upper region is wider in diameter, where the straight region joins the upper region, than the straight region through a stepped portion formed between the straight region and the upper region, wherein the lower region is the same diameter as the straight region, and wherein the heel portion is wider in diameter, where the heel portion joins the lower region, than the lower region through a stepped portion formed between the heel portion and the lower region.