A non-spherical tank for storing a liquefied gas, the non-spherical tank comprising: a circular cylindrical portion extending along a vertical direction and having a cylindrical shape; a top portion having a head plate structure where the top portion is disposed continuously with an upper side of the circular cylindrical portion and projects upward; and a bottom portion having a head plate structure where the bottom portion is disposed continuously with a lower side of the circular cylindrical portion and projects downward, wherein the top portion includes: a top-portion-side spherical shell portion which is formed of a portion of a spherical body having a first radius R1, and is disposed at an upper end of the top portion; and a top-portion-side toroidal portion which is disposed continuously with the upper side of the circular cylindrical portion and with a lower side of the top-portion-side spherical shell portion, and is formed of a portion of a spherical body having a second radius R2 smaller than the first radius R1, characterized in that the following conditional expressions are satisfied: 1.2 ≤ R / H 1 < 1.45 R 1 / R 2 < 2.5 and R 2 / R > 0.4 where "R" denotes a radius of the circular cylindrical portion and "H1" denotes a height of the top portion in the vertical direction. a circular cylindrical portion extending along a vertical direction and having a cylindrical shape; a top portion having a head plate structure where the top portion is disposed continuously with an upper side of the circular cylindrical portion and projects upward; and a bottom portion having a head plate structure where the bottom portion is disposed continuously with a lower side of the circular cylindrical portion and projects downward, wherein the top portion includes: a top-portion-side spherical shell portion which is formed of a portion of a spherical body having a first radius R1, and is disposed at an upper end of the top portion; and a top-portion-side toroidal portion which is disposed continuously with the upper side of the circular cylindrical portion and with a lower side of the top-portion-side spherical shell portion, and is formed of a portion of a spherical body having a second radius R2 smaller than the first radius R1, characterized in that the following conditional expressions are satisfied: 1.2 ≤ R / H 1 < 1.45 R 1 / R 2 < 2.5 and R 2 / R > 0.4 where "R" denotes a radius of the circular cylindrical portion and "H1" denotes a height of the top portion in the vertical direction. a top-portion-side spherical shell portion which is formed of a portion of a spherical body having a first radius R1, and is disposed at an upper end of the top portion; and a top-portion-side toroidal portion which is disposed continuously with the upper side of the circular cylindrical portion and with a lower side of the top-portion-side spherical shell portion, and is formed of a portion of a spherical body having a second radius R2 smaller than the first radius R1, characterized in that the following conditional expressions are satisfied: 1.2 ≤ R / H 1 < 1.45 R 1 / R 2 < 2.5 and R 2 / R > 0.4 where "R" denotes a radius of the circular cylindrical portion and "H1" denotes a height of the top portion in the vertical direction.