The characteristics of the surface waves guided along a perfectly conducting infinite cylinder are investigated for the case in which it is immersed in a magnetoionic medium and oriented so that its axis is parallel to the direction of the magnetostatic field. The surface waves are found to be propagated along the cylinder for frequencies less than the plasma or the gyromagnetic frequency of the electrons, whichever is lower. The phase velocity of the surface waves is always less than the velocity of electromagnetic waves in free space. The dependence of the characteristics of the surface waves on the radius of the cylinder is also examined.