  We study effects of a chiral helimagnet (CHM) on vortex states in a
superconductor, solving the Ginzburg-Landau equations in a chiral
helimagnet/superconductor bilayer system. We found that vortices form a
periodically modulated triangular lattice, because the magnetic field from the
chiral helimagnet $H_{CHM}$ oscillates spatially. An increase of a critical
current is expected, because vortices are pinned by the $H_{CHM}$.
