Hydrogen entry into AISI 4135 high strength steel in tribocorrosion environment was studied in the present study. The samples were corroded in tribocorrosion environment using a pin-on-disk type wear gear equipped with a solution cell and in static corrosion environment, and the hydrogen content entered into the steel was measured using hydrogen thermal desorption analysis. The hydrogen content in tribocorroded sample was larger than that in corroded sample without wear. From the cathodic polarization curves and surface morphology, it is revealed that the main factor which increases the amount of entered hydrogen is solution flow. The solution flow enhances the supply of oxygen, and the difference of flow rate forms anodic and cathodic areas on the samples. Solution flow also enhances anodic dissolution and increases hydrogen generation reaction. As a result, hydrogen entry into the high strength steel is enhanced in tribocorrosion environment.