The article sets forth the new concept of structure of the Stirling engine. Specific realizations of that idea have been discussed. The modification consists in replacing the crank system with the cam mechanism. As a result, the stages of heating and cooling of working gas are longer and transitory stages are shorter. The aim is to obtain higher efficiency in relation to the already existing solutions and to simplify the engine structure. The visualisation of its structure and the principle of operation have been presented. The proper shaping of the cam mechanism allowed for the change of the significant parameters influencing its efficiency. The use of such type of engine allows for the use of heat energy lost in many technological processes and installations.