A cement clinker which can be sintered at 1,300 to 1,400° C. which is lower than the conventional sintering temperature and develops excellent strength characteristics such as mortar compression strength.The cement clinker has a total content of C3A and C4AF calculated by Bogue's formulas of 22 mass % or more, a C3S content calculated by Bogue's formula of 60 mass % or more and an iron modulus (I.M.) of 1.3 or less, preferably 1.0 to 1.3. Since the total content of C3A and C4AF is 22 mass % or more, the cement clinker can be sintered at a low temperature and the reduction of strength when a cement composition is cured can be prevented by reducing the iron modulus of the cement clinker.