A self-balancing pressure hull device, belonging to the field of pressure structure technology of deep-sea submersibles, being assembled by nesting, from inside to outside, a spherical inner housing, a spherical intermediate housing and a spherical outer housing around the sphere center, pairs of symmetric coaxial connecting shaft components being connected between the spherical inner housing and the spherical intermediate housing and between the spherical intermediate housing and the spherical outer housing, respectively; axes of the two pairs of connecting shaft components are perpendicular to each other so as to enable the spherical inner housing and the spherical intermediate housing to rotate relative to each other, and the spherical intermediate housing and the spherical outer housing to rotate relative to each other, and each of the connecting shaft components in the two pairs being provided with a spring damper for resisting the axial impact between each two adjacent housings.