An apparatus for interpreting an image position is used for respectively reflecting an image of a target to a lens of at least one camera by means of first and second reflection mirrors to be respectively taken a photo as first and second images by the lenses. A microprocessor processes the first and the second images to obtain a relative coordinate value of a target in an operation plane range. A horizontal optical axis of at least one camera is parallel to the operation plane. Whereby, a position of an input zone touched by a user is interpreted more quickly so as to elevate the inputting efficiency of a data input device, and whether the user touches the input zone is interpreted more accurately so as to elevate the inputting accuracy of the data input device.