A small and high-strength spiral bevel gear fabricated using a five-axis controlled machining center has been developed in the gear manufacturing fields. We propose a novel spiral bevel pinion with ribs at the end of the face width to reinforcethe tooth bending strength, which is machined with a ball-nose end-mill tool and estimate its rib shape with a 1D-CAE method. In the present report, we fabricated a prototype pinion with ribs based on 1D-CAE results and discussed the influence of the ribs on the stress at the tooth root and fillets around rib with strain gages under running conditions in the experiment. As a result, it can be seen that the ribs decrease the tooth root stress and makes the tooth contact movement smaller due to driving torque variation.