PURPOSE: To prevent erroneous recording and to attain conforming to recording and reproducing and making a light source long life by irradiating an optical recording medium in the state of stand-by, still at a non operating time with a light source point whose emission state, emission are controlled by a prescribed amount and executing focusing, tracking adjustment with an optical head.

CONSTITUTION: The optical medium 1 is moved relatively to the optical head having a semiconductor element 54, etc., and the medium 1 is scanned, and the recording and reproducing are performed. At a non operation time, a laser beam outgoing from the element 54 intermittent emission controlled irradiates the medium 1 in the state of still at a stand-by position, and the light quantity of a reflection beam from the medium 1 is measured by a measuring instrument 60, and the focusing, tracking adjustment by an objective lens 57 are executed through a controller 30. Thus, erroneous bit recording is prevented without increasing the storage of energy, and the recording and reproducing are conformed without necessitating the adjustment of focusing, etc., newly, and the life of the light source is prolonged compared with continuous emission.