PURPOSE: To simplify the structure of a device and also facilitate its operation by setting an operation tool under the condition of a coloring or discoloring effect state relative to the recording paper when the detection part detects projection light higher than the strength in a part.

CONSTITUTION: A heat sensitive recording pen 2 as an operation tool is constituted of a heating body 20, a hollow light conduit 61 provided in the pen, a light incident hole 60 for letting light into the light conduit 61 from the outside, and a light receiving element 62 provided on the distal end of the light conduit 61. The light receiving element 62 passes through the light incident hole 60 and light conduit 61 and produces signal voltage according to the strength of incident light. The comparator circuit 64, when the output voltage value of the light receiving element 62 is beyond the voltage of the standard voltage generating circuit 63, generates control signals being transmitted to the input voltage to the output by a heat body control circuit 23, and when the output voltage value of the light receiving element 62 is below the voltage of the standard voltage producing circuit 63, it generates signals for interrupting the transmission of the input voltage to the output.