An optical touch screen comprising: a main body configured to enclose edges of a touch area of a screen; fine coordinate infrared light source generators (120A, 120B, 120C, 120D) configured to be arranged on each of two horizontal sides and two longitudinal sides of the main body and facing toward the touch area so as to generate a plurality of infrared light sources forming fine coordinates at a predefined spacing and to provide references for coordinates in a horizontal axis and a vertical axis of the touch area; two or more infrared cameras (130A, 130B, 130C) configured to be installed in the main body to detect the infrared light sources forming fine coordinates generated by the fine coordinate infrared light source generators (120A, 120B, 120C, 120D); and a control unit configured to calculate coordinates of an object being touched in the touch area on the basis of detection data obtained by the infrared cameras (130A, 130B, 130C), wherein each of the fine coordinate infrared light source generators (120A, 120B, 120C, 120D) comprises at least one infrared light emitting unit and a fine-coordinate-light source distributor configured to distribute light emitted from the infrared light emitting unit to the infrared light sources forming fine coordinates at a predefined spacing, wherein the fine-coordinate-light source distributor comprises a transparent rod having the infrared light emitting unit on one end, characterized in that the transparent rod has fine grooves formed at a predefined spacing on one side along a length direction such that the fine-coordinate-light source distributor allows light diffuse-reflected by the fine grooves to generate the infrared light sources forming fine coordinates at a predefined spacing on the other side, wherein the side of the transparent rod on which the infrared light sources forming fine coordinates are generated has a curved surface to function as a lens, wherein the side of the transparent rod on which the fine grooves are formed has a curved surface so that the light diffuse-reflected by the fine grooves is focused inside the transparent rod, and wherein the transparent rod further comprises a reflection member on the side where the fine grooves are formed. a main body configured to enclose edges of a touch area of a screen; fine coordinate infrared light source generators (120A, 120B, 120C, 120D) configured to be arranged on each of two horizontal sides and two longitudinal sides of the main body and facing toward the touch area so as to generate a plurality of infrared light sources forming fine coordinates at a predefined spacing and to provide references for coordinates in a horizontal axis and a vertical axis of the touch area; two or more infrared cameras (130A, 130B, 130C) configured to be installed in the main body to detect the infrared light sources forming fine coordinates generated by the fine coordinate infrared light source generators (120A, 120B, 120C, 120D); and a control unit configured to calculate coordinates of an object being touched in the touch area on the basis of detection data obtained by the infrared cameras (130A, 130B, 130C), wherein each of the fine coordinate infrared light source generators (120A, 120B, 120C, 120D) comprises at least one infrared light emitting unit and a fine-coordinate-light source distributor configured to distribute light emitted from the infrared light emitting unit to the infrared light sources forming fine coordinates at a predefined spacing, wherein the fine-coordinate-light source distributor comprises a transparent rod having the infrared light emitting unit on one end, characterized in that the transparent rod has fine grooves formed at a predefined spacing on one side along a length direction such that the fine-coordinate-light source distributor allows light diffuse-reflected by the fine grooves to generate the infrared light sources forming fine coordinates at a predefined spacing on the other side, wherein the side of the transparent rod on which the infrared light sources forming fine coordinates are generated has a curved surface to function as a lens, wherein the side of the transparent rod on which the fine grooves are formed has a curved surface so that the light diffuse-reflected by the fine grooves is focused inside the transparent rod, and wherein the transparent rod further comprises a reflection member on the side where the fine grooves are formed.