The present invention relates to an optical touch screen which can recognize touch coordinates when the screen is touched by a finger, a touch pen, or the like. The optical touch screen comprises a main body, units for generating infrared light forming fine coordinates, two or more infrared cameras, and a control unit. The main body is arranged to cover the edge of a touch area of a screen. The units for generating infrared light forming fine coordinates are arranged at the two horizontal sides and two vertical sides of the main body at a regular spacing and facing toward the touch area so as to generate infrared light forming fine coordinates, and provide references for coordinates in a horizontal axis and a vertical axis. The infrared cameras are installed in the main body to detect the infrared light forming fine coordinates generated by the units for generating infrared light forming fine coordinates. The control unit calculates coordinates of the object being touched in the touch area on the basis of data detected by the infrared cameras.