Provided is a device to be implanted in vivo, which can exhibit antibacterial activity simply by being implanted in vivo, in order to reduce patient load. This device to be implanted in vivo comprises a first material and a second material, wherein at least the surface of the first material includes an antibacterial metal, at least the surface of the second material is more precious than the first material, when used implanted in vivo an electrical circuit is formed between the first material and the second material, antibacterial metal ions are eluted from the first material in the presence of an electrolyte, and antibacterial action is exhibited on the surface and/or in the proximity of the surface of the first material.
