Provided is a power conversion system having a solid-oxide fuel cell capable of stably generating electricity from hydrogen generated by an organic hydride. The power conversion system includes a solid-oxide fuel cell, a reactor for producing hydrogen and a dehydrogenation product from an organic hydride by dehydrogenation reaction, and a heat engine for generating motive power. The power conversion system separates the hydrogen produced by the reactor, and supplies the hydrogen as fuel to the solid-oxide fuel cell. Exhaust heat of the heat engine is supplied to both the solid-oxide fuel cell and the reactor.