PURPOSE: To provide an optical touch tablet which is provided with a remarkably smaller number of constituting elements and mutual connections than conventional technique, reducing the number of mutual connections between a control means and a receiver or a transmitter and consumes totally little power compared with the device of a conventional technique. CONSTITUTION: A data input device 10 includes the touch tablet 12 provided with a positioning means 14 positioning an object with respect to the touch tablet 12 by detecting an object 16 interrupting light beams between plural light beam transmitters T1 to TN and plural light beam receivers R1 to RM. Each transmitter T1 to TN can simultaneously transmit the light beams to the plural consecutive receivers R1 to RM. The positioning means 14 positions the object based on the positions of at least first and second non-overlapped shadow areas SZ1 and SZ2 projected to the first and second plurally connected receivers among the receivers R1 to RM as the result of the object 16 interrupting the light beams from the first and second transmitters among the respective transmitters R1 to RM. COPYRIGHT: (C)1994,JPO