Provided is a substrate/oriented apatite-type composite oxide film complex which is suitable as a solid electrolyte for a battery, a sensor, a separation membrane, or the like, and can be produced inexpensively. Proposed is a substrate/oriented apatite-type composite oxide film complex provided with an oriented apatite-type composite oxide film on a substrate, wherein a film thickness of the oriented apatite-type composite oxide film is 10.0 μm or less, a degree of orientation (Lotgering method) thereof is 0.6 or more, and a material of the substrate at a side on which at least the oriented apatite-type composite oxide film is formed is a metal, an alloy, a ceramic, or a composite material thereof.