This paper aims to show that the plasma structures of both the outer heliosphere and of some planetary nebulae whose stars have magnetic field can be discussed under similar MHD physical processes. It is shown that the magnetic pressure force of the toroidal field works azimuthaly to push up the plasma in a polar direction, while at the same time pushing down in an equatoward direction from the region where the toroidal field intensity is maximum. As an example of interplanetary nebulae, the three‐ring structure around SN 1987A observed by the Hubble Space Telescope is discussed. It is shown that this structure is reproduced by a MHD simulation due to magnetic‐pressure effects if we assume that the star has a relatively strong dipole magnetic field and that the stellar wind is fast in the high‐latitude coronal hole region, such as in the case of the Sun. It is also shown for the heliospheric structure that, if the magnetic effect around the equatorial neutral sheet is taken into accout, the global heliospheric structure is not a simple nose‐cone type but a V‐shaped gutter structure along the equatorial plane on the nose‐cone surface of the heliopause. © 2004 American Institute of Physics