<p>For a power generation apparatus to efficiently extract rotational driving force generated by an expander to the exterior of a housing that contains the expander while preventing a working medium from leaking, the power generation apparatus according to the present invention includes a housing that contains a driving unit of the expander within a space enclosed by a partition wall, and a magnetic coupling that is divided between the inside and outside of the housing through the partition wall and that transmits the rotational driving force of the expander to the exterior of the housing.</p>