PURPOSE: To highten the thermal efficiency of a solar engine, by focussing parallel light rays with the use of a light focussing member having a parabolic reflecting surface, and by arranging the light focussing member so that it is right in opposite to the sun light with the use of the thermal expansion of resilient wires.

CONSTITUTION: A parabolic reflecting surface focuses parallel light rays to a heat pipe positioned at the focal point thereof for multiplying the light beam density thereof. The heat pipe having a bulk and a surface area, occupies a predetermined space around the focal point. An optic-mechanical method of holding the parabolic reflecting surface right in opposite to the sun, is such that the work attending the expansion and contraction of resilient wires is utilized. At this time, since the extension and contradiction of the resilient wires which are very small, are taken out, externally, after they are amplified by a travel amplifier mechanism, the thermal efficiency of the solar engine may be enhanced.