A lead-free steel for machine structural use with excellent machinability and low strength an isotropy, which does not contain Pb and is equal to or higher than a conventional D Pb-containing free cutting steel in properties, is provided. This steel includes, on the weight basis, C: 0.10 to 0.65%; Si: 0.03 to 1.00%; Mn: 0.30 to 2.50%; S: 0.03 to 0.35%; Cr: 0.1 to 2.0%; Al: less than 0.010%; Ca: 0.0005 to 0.020%; Mg: 0.0003 to 0.020%; 0: less than 20 ppm; and the balance being Fe and inevitable impurities.