PURPOSE: To obtain pattern arrangement without moire and unbalanced density, by using lower-order bit information of input picture information as the expression of intermediate tone of recorded picture, and expressing the intermediate tone having the same degree as that of the input picture information.

CONSTITUTION: An intermediate tone expressing circuit provides a counter 205 and an adder 208 for a conventional circuit and the gradation the same degree as that of an input gradation information amount can be recorded and expressed with less basic density pattern number, by controlling the probability of appearance of a dither signal with an overflow bit 209 in response to picture information read from an original. In this expressing method, when the input signal level to select the pattern of k×l gradation expresses the more gradation, the lower- order gradation number is appeared periodically or at random and the gradation is summed to an original input signal and sliced to the levels of k×l stages to obtain the input signal to select the number of gradation stages.