PURPOSE: To manufacture a chemical diode usable as a component of a viochip by a method wherein an easily reducing material as an electron receptor and a reversibly oxidizing and reducing material as a mediator are laid between an opposite pole as a positive electrode and a working pole as a negative electrode.

CONSTITUTION: An easily reducing material 2a as an electron receptor and a reversibly oxidizing and reducing material 3a as a mediator are laid between an opposite pole 1 as a positive electrode and a working pole 4 as a negative electrode. Or an easily oxidizing material 2b as an electron donor and a reversibly oxidizing and reducing material 3b as a mediator are laid between an opposite pole 1 as a negative electrode and a working pole 4 as a positive electrode. For example, the opposite pole 1 and the working pole 4 are oppositely arranged and the easily reducing material 2a as the electron receptor, e.g., ferritin fixed to a porous medium is provided between the opposite pole 1 and the working pole 4 while the reversibly oxidizing and reducing material 3a, e.g., ascorbic acid is spread to said porous medium.