A hydrogen production microelectrode optical fiber (1), optical cable (11), and hydrogen production device for light supplementary electrolysis of water. The microelectrode optical fiber (1) comprises a light guide core (2). The light guide core (2) has at least a first light guide section (A) and a second light guide section (B); in the first light guide section (A), the light guide core (2) is sequentially provided with a light absorption layer (3), an inner electrode layer (4), an insulating layer (5), a void layer (6), a proton exchange membrane (8) and an outer electrode layer (9) from inside to outside; and in the second light guide section (B), the light guide core (2) is provided with a conductive layer (10) that is connected with the inner electrode layer (4). The hydrogen production optical cable (11) comprises a protective casing (12) and microelectrode optical fibers (1) that are encapsulated and bundled therein. The hydrogen production device comprises an electrolyte bath (13), a hydrogen production optical cable (11), an inner electrode bus, an outer electrode bus, and an optical fiber distributing device. Each microelectrode optical fiber (1) in the hydrogen production optical cable (11) is distributed in the electrolyte (14); and the outer electrode layer (9) and the conductive layer (10) in each microelectrode optical fiber (1) are respectively connected with the inner electrode bus and the outer electrode bus. The hydrogen production device uses solar energy as a supplement to electric energy, effectively reducing electric energy consumption, increasing the space-time yield of hydrogen.