There is provided a process of producing a multicrystalline silicon substrate having excellent characteristics as a solar cell substrate. A multicrystalline silicon ingot made by directional solidification 10 is cut such that a normal line of a principal surface 14 of a multicrystalline silicon substrate 13 is substantially perpendicular to a longitudinal direction of crystal grains 11 of the multicrystalline silicon ingot made by directional solidification 10.