A high strength and high toughness cast steel material of the invention has a composition comprising 0.10 to 0.20% by mass of C, 0.10 to 0.50% by mass of Si, 0.40 to 1.20% by mass of Mn, 2.00 to 3.00% by mass of Ni, 0.20 to 0.70% by mass of Cr, and 0.10 to 0.50% by mass of Mo, and further comprising Fe and unavoidable impurities. The high strength and high toughness cast steel material of the invention is produced by subjecting an ingot having the above composition to annealing at 1,000 to 1,100° C., quenching at 850 to 950° C., tempering at 610 to 670° C., and then, if desired, stress-relief annealing at less than 610° C.