A bottle formed of a synthetic resin material in a cylindrical shape with a bottom having a bottom wall portion , the bottom wall portion comprising: a grounding portion located at an outer circumferential edge of the bottom wall portion ; a rising circumferential wall portion that is connected from a bottle radial inner side to the grounding portion and extends; an annular movable wall portion protruding from an upper end of the rising circumferential wall portion towards the bottle radial inner side and a recessed circumferential wall portion that is connected from the bottle radial inner side to the movable wall portion and extends upward wherein: the movable wall portion is free to rotate around a curved surface part connected to the rising circumferential wall portion so as to move the recessed circumferential wall portion in an upward direction , the curved surface part protrudes upward, and the rising circumferential wall portion extends upwardly and inwardly from the grounding portion to the curved surface part , an inclined angle (θ) thereof is equal to or less than 10° with respect to a central longitudinal axis (O) of the bottle , characterized in that the contents of the bottle are equal to or less than one liter and in that a grounding diameter is equal to or less than 85 mm,_and a height (T, H2) from the grounding portion to the curved surface part exceeds 7.5 mm. a grounding portion located at an outer circumferential edge of the bottom wall portion ; a rising circumferential wall portion that is connected from a bottle radial inner side to the grounding portion and extends; an annular movable wall portion protruding from an upper end of the rising circumferential wall portion towards the bottle radial inner side and a recessed circumferential wall portion that is connected from the bottle radial inner side to the movable wall portion and extends upward wherein: the movable wall portion is free to rotate around a curved surface part connected to the rising circumferential wall portion so as to move the recessed circumferential wall portion in an upward direction , the curved surface part protrudes upward, and the rising circumferential wall portion extends upwardly and inwardly from the grounding portion to the curved surface part , an inclined angle (θ) thereof is equal to or less than 10° with respect to a central longitudinal axis (O) of the bottle , characterized in that the contents of the bottle are equal to or less than one liter and in that a grounding diameter is equal to or less than 85 mm,_and a height (T, H2) from the grounding portion to the curved surface part exceeds 7.5 mm. the movable wall portion is free to rotate around a curved surface part connected to the rising circumferential wall portion so as to move the recessed circumferential wall portion in an upward direction , the curved surface part protrudes upward, and the rising circumferential wall portion extends upwardly and inwardly from the grounding portion to the curved surface part , an inclined angle (θ) thereof is equal to or less than 10° with respect to a central longitudinal axis (O) of the bottle , characterized in that the contents of the bottle are equal to or less than one liter and in that a grounding diameter is equal to or less than 85 mm,_and a height (T, H2) from the grounding portion to the curved surface part exceeds 7.5 mm. <EOS>