A spherical casting sand having an average particle diameter of 0.03 to 1.5 mm, produced by a flame fusion method, usable together with a urethane binder. Casting sands capable of producing a mold having higher strength and excellent surface smoothness without deformation or breakage with fewer gas defects in producing a mold by using a urethane binder in the cold box process or in the urethane self-hardening mold making method. The casting sand has longer bench life in the cold box process. Amount of generated gas that is a problem of the mold making method using a urethane binder can be significantly reduced, and a casting with fewer gas defects can be obtained.