A non-heat treated connecting rod which comprises, by mass %, C: 0.25-0.35%, Si: 0.50-0.70%, Mn: 0.60-0.90%, P: 0.040-0.070%, S: 0.040-0.130%, Cr: 0.10-0.20%, V: 0.15-0.20%, Ti: 0.15-0.20% and N: 0.002-0.020%, and the balance Fe and impurities, with chemical compositions being less than 0.80 in the value of C+(Si/10)+(Mn/5)+(5Cr/22)+1.65 V−(5S/7) using the symbol of the element as its content, the microstructure of the Big end of the said connecting rod being ferrite-pearlite, all-region hardness of the said big end being 255 to 320 in Vickers hardness, the ferrite-region hardness in the said ferrite-pearlite of the Big end being 250 or more in Vickers hardness and the ratio of the said ferrite-region hardness to the said all-region hardness of the said Big end being 0.80 or more, is excellent in machinability, fracture splitting ability, and fatigue resistance, although no Pb at all is added. Therefore, this non-heat treated connecting rod can be utilized as a low cost type connecting rod in automobile engines or the like.