An artificial mitochondoria has been devised without using whole cells or organelles and cell‐free enzymes. It has been successful due to an electrically conductive titanium nitroxicarbide base ceramics. Each of ATP phosphorylation and NADH oxidation has been conducted electrolytically with an external voltage supply in each electrochemical cell using an electrode made of that material. Moreover, each of them has been carried out galvanically while consuming and generating electricity in each electrochemical cell using the electrode. From experimental results, a chemical mechanism of mitochondorial oxidative phosphorylation coupled to NADH oxidation has been explained completely concerning the P:O ratio. Generally, phosphorylation coupled to NADH oxidation at the P:O ratio is achieved by combining two galvanic NADH oxidation cells of this study, and the galvanic and electrolytic phosphorylation cells of this study by .