To provide a laser ignition type engine capable of restraining an increase in useless manhours caused by the replacement of a target and the occurrence of an evil such as operation stopping of an engine, by preventing the occurrence of laser ignition failure by reduction in the service lift of the target and combustion failure caused thereby, by preventing reduction in the service lift of the target by one point concentrated irradiation of a laser beam by avoiding concentrated irradiation of the laser beam to one point of the target.

This laser ignition type engine is constituted so as to ignite gas in a combustion chamber by plasma generated by irradiating the laser beam from a laser oscillating device 1 to the target in the combustion chamber 13 formed in an upper part of a piston. One surface of an opening-closing valve such as an intake valve 14, an exhaust valve and a gas supply valve 26 arranged by facing the combustion chamber, is formed in the target capable of irradiating the laser beam. An opening-closing valve moving means is arranged for moving the target of the opening-closing valve by a very small quantity. The laser beam is irradiated to the target while moving the opening-closing valve by the very small quantity by the opening-closing valve moving means.