Multiple- spin order, i.e., a spin texture characterized by a multiple number of coexisting magnetic modulation vectors , has recently attracted attention as a source of nontrivial magnetic topology and associated emergent phenomena. One typical example is the triple- skyrmion lattice state stabilized by Dzyaloshinskii-Moriya interactions in noncentrosymmetric magnets, while the emergence of various multiple- states of different origins is expected according to the latest theories. Here, we investigated the magnetic structure of the itinerant polar hexagonal magnet Y Co Sn , in which several distinctive mechanisms favoring multiple- states are allowed to become active. Small-angle neutron-scattering experiments suggest the formation of incommensurate triple- magnetic order with an in-plane vortex-like spin texture, which can be most consistently explained in terms of the novel four-spin interaction mechanism inherent to itinerant magnets. The present results suggest a new route to realizing exotic multiple- orders and that itinerant hexagonal magnets, including the Sn family with wide chemical tunability, can be a unique material platform to explore their rich phase diagrams.