PURPOSE: To restrain an amount of fuel sticking to the upper face of a piston as well as restraining injection fuel blow-by in a high speed rotation region by providing a two cycle engine of cylinder injection type with a compressed air injection means which injects compressed air from a gap between an exhaust passage and an exhaust valve toward the inside of a cylinder.

CONSTITUTION: An air fuel injector 13 mounted on a cylinder head 4 is composed of a body part 14 having a valve body 14c therein to open and close an injection nozzle 14b and a fuel injection valve 15 fixed to the body part 14. In this case, a combustion recess part 4a composing a combustion chamber 13 together with the upper face of a piston 6 is installed at the lower face of the cylinder head 4 so as to face the injection nozzle 14b to the center of the combustion chamber 12. An air passage 3c for a compressed air injection mechanism 17 is formed in the upper part of an exhaust valve 11 for a cylinder body 3 to communicate the air passage 3c with an air pump 28 through an air passage 27 and intermediarily install an open/close valve 29 to be controlled by a controller 30 on the way of the air passage 27.