We report long periodic chiral helimagnetic orderings in ferromagnetic inorganic compounds CrM3S6(M = Nb and Ta) with a chiral space group of P6322. Magnetization in polycrystalline samples and high resolution powder neutron diffraction were measured. Our powder neutron diffraction measurements in CrM3S6successfully separated nuclear and magnetic satellite peaks, having the period of hundreds of angstroms along the c-axis. Therefore, we propose that the magnetic ordering in ferromagnetic CrM3S6 is not ferromagnetic, but long periodic chiral helimagnetic ordering. 漏 Published under licence by IOP Publishing Ltd.