  Formation of the triangular skyrmion-lattice is found in a tetragonal polar
magnet VOSe$_2$O$_5$. By magnetization and small-angle neutron scattering
measurements on the single crystals, we identify a cycloidal spin state at zero
field and a N\'eel-type skyrmion-lattice phase under a magnetic field along the
polar axis. Adjacent to this phase, another magnetic phase of an incommensurate
spin texture is identified at lower temperatures, tentatively assigned to a
square skyrmion-lattice phase. These findings exemplify the versatile features
of N\'eel-type skyrmions in bulk materials, and provide a unique occasion to
explore the physics of topological spin textures in polar magnets.
