A cast steel shot media for performing a blasting treatment, including, at a weight ratio, 0.8% or more and 1.2% or less of C, 0.35% or more and 1.2% or less of Mn, and 0.4% or more and 1.5% or less of Si, in which a remainder has a hyper-eutectoid composition including Fe and inevitable impurities, and the cast steel shot media has a structure having a fine pearlite structure as a main constituent.