Patent ID: 6981604

Claim:
A bottle-shaped container made of synthetic resin including a body that has a left side and a right side which are symmetric to each other to a central axis line of the container, wherein each of the left and right sides is formed in a region including a center of the body, with a concaved portion configured to absorb distortion due to changes of an internal pressure of the container; the concaved portions in the right and left sides are conformable in shape each other, and have same dimensions, each of said concaved portions includes an upper edge, a lower edge and a bottom wall, said bottom wall is in a form of shallowly concaved arc in at least one direction of a longitudinal direction and a lateral direction of a circumferential wall of the body, each of the concaved portion is formed with protruded reinforcing portions at to an upper and lower portion thereof, and each of the reinforcing portions has a height gradually reduced from the upper or lower edge to the bottom wall, and a lateral width gradually reduced from the upper or lower edge to the bottom wall, so that the reinforcing portion has a substantially triangular shape.