Ferroelectricity induced by magnetic ordering with certain type of magnetic structure has received much attention because it provides opportunity to manipulate magnetization by electric field or vice versa. We have discovered ferroelectricity in two different phases of MnSb2S4 below the magnetic ordering temperature. We need to understand the type of magnetic structure which is responsible for inducing ferroelectricity in these phases. For this purpose we would like to perform neutron diffraction in the two phases of MnSb2S4.