A heat energy recovery system includes an evaporator, a superheater, an expander, a power recovery device, a condenser, a pump, and a controller. The controller includes: an engine load calculation section; a maximum rotation speed determination section for determining a maximum rotation speed of the pump which is obtained when a pinch temperature reaches a target pinch temperature, based on a relational expression representing a relationship between the engine load and the maximum rotation speed, and an engine load; and a rotation speed regulation section for regulating the rotation speed of the pump in such a way as to allow the degree of superheat of the working medium flowing into the expander to be equal to or greater than a reference value, and to allow the rotation speed to be equal to or less than a maximum rotation speed determined by the maximum rotation speed determination section.