PURPOSE: To improve accuracy for a recognition processing when a picture is written with the plural stages of density by recognizing inputted character and graphic patterns based on the plural kinds of the density decided by a recognition density deciding means, and displaying recognized results in stages.

CONSTITUTION: A time chart 1 is scanned by a scanning means 2 and the distribution of black picture elements in an obtained waveform pattern, for example, is calculated by a recognition density deciding means 10 so as to determine reference density 11. In a recognizing means 5a, recognition is executed respectively to the density 11 obtained by the means 10, a value 12 deviating the density 11 to shade and a value 13 deviating the density 11 to light, and the recognized results are stored in a storing means 6. In a control means 9a, based on the recognized results stored in the means 6, the probability of the recognition is calculated and the recognized results are displayed by a display means 7 in stages with a method to change a color, for example. When unreadable characters or erroneously read characters are existent in the recognized results displayed in stages, a worker executes correction work by using an input means 8. Thus, even when the picture is written to a recording medium with the plural stages of the density, the recognition processing is executed with the high accuracy.