Provided is a method of treating a surface of a mold to achieve good demoldability and capable of preventing wearing of the mold by avoiding load concentration on one part of the surface of the mold. After a first blasting is performed on the surface of the mold to remove a hardened layer produced on the surface and/or to adjust the surface roughness, a second blasting is performed to create fine irregularities on the surface. Then, an elastic abrasive in which abrasive grains are carried on an elastic body, or a plate-like abrasive having a planar shape with a maximum length that is 1.5 to 100 times the thickness thereof, is ejected onto the surface of the mold at an inclined ejection angle such that the abrasive is caused to slide along the mold surface to flatten peaks of the irregularities created on the mold surface.