PURPOSE: To improve castability by adding relatively large amounts of Ni and balancing adjustment of other components with the Ni addition, e.g. by reducing C content, increasing Cr content, etc., in a martensitic stainless steel with a specific composition.

CONSTITUTION: This martensitic stainless cast steel has a composition consisting of ≤0.06% C, ≤2% Si, ≤2% Mn, 3-6% Ni, 14-17% Cr, 1-3 Mo, 0.5-1.5% Cu, and the balance Fe. Since this cast steel has superior castability and also has excellent strength, hardness, ductility, toughness, etc., it can be suitably used, e.g. for suction roll material for paper making. In this cast steel, Ni is effective in improving hardenability and compensating deterioration in strength due to reduction in C content as well as in improving castability, and further, it has a function of inhibiting embrittlement at the time of tempering treatment after hardening treatment and prevents deterioration in corrosion resistance.