A combustion-type power tool includes a cylinder having a peripheral wall which has an inner peripheral surface and an outer peripheral surface. The peripheral wall is formed with an exhaust hole at a first axial position. A piston is reciprocally movable in an axial direction and is slidable in contact with the inner peripheral surface. A combustion-chamber frame is abuttable on a head portion to provide a combustion chamber in cooperation with the head portion and the piston. The piston allows the combustion chamber to be in fluid communication with an atmosphere through an upper space above the piston and through the exhaust hole when the piston is located at a bottom dead center. The fin is disposed at the outer peripheral surface and has a portion extending in a direction slanted in relation to the axial direction and oriented toward the exhaust hole.