A non-heat treated steel bar according to the present disclosure has a chemical composition consisting of, in mass percent, C: 0.39 to 0.55%, Si: 0.10 to 1.00%, Mn: 0.50 to 1.50%, P: 0.010 to 0.100%, S: 0.040 to 0.130%, Cr: 0.05 to 0.50%, V: 0.05 to 0.40%, Ti: 0.10% to 0.25%, Al: 0.003 to 0.100%, and N: 0.020% or less, with the balance being Fe and impurities, and satisfying Formula (1). A number density of Al2O3-based inclusions in each of which Al2O3 is contained at 70.0% or more in mass % and √AREA is not less than 3 μm is 0.05 to 1.00/mm2. 0.60≤C+0.2Mn+0.25Cr+0.75V+0.81Mo≤1.00  (1)