An external combustion engine provided with a plurality of evaporators and stabilized in output and efficiency, that is, an engine provided with at least one main container, a plurality of evaporators heating the working medium to evaporate, condensers cooling the vapor of the working medium evaporated at the evaporators to make it condense, an output part communicated with the other end of the main container and converting displacement of a liquid part of the working medium occurring due to fluctuations in volume of the working medium accompanying evaporation and condensation of the working medium to mechanical energy for output, a single main container pressure adjusting means adjusting an internal pressure of the main container, and controlling means for controlling the main container pressure adjusting means based on a lowest temperature in the temperatures of the plurality of evaporators constituting a minimum evaporator temperature.