Provided is a pressure vessel. An example pressure vessel includes a spherical portion and a conical portion that extends from the spherical portion and has an opening for pumping in and pumping out a pressurized gaseous substance. The spherical portion and the conical portion are made in a single technological cycle by 3D printing. The thicknesses of the wall of the spherical portion changes from δ 1 = P ⁢ R 1 2 ⁢ [ σ ] to δ 2 = 3 ⁢ P ⁢ R 2 2 ⁢ [ σ ] ⁢ ⁢ cos ⁢ ⁢ α and the thickness of the wall of the conical portion changes linearly from δ2 to δ 3 = 3 ⁢ P ⁢ R 3 2 ⁡ [ σ ] ⁢ ⁢ cos ⁢ ⁢ α , where P is predetermined operating pressure, R1 is a radius of the spherical portion, R2 is a radius of a base of the conical portion, R3 is a radius of the opening of the conical portion, [σ] is an allowable material stress, and a is an angle between a generatrix and a symmetry axis of the conical portion.