To obtain an output picture with high resolution by outputting picture data obtained by conducting an edge emphasizing processing to a noticing pixel wen the density value of a noticing pixel is lower than a prescribed reference threshold value and outputting picture data as it is when the density is higher than the reference threshold value.

A noticing pixel selecting circuit 9 selects a pixel to picture- process as a successive noticing pixel. A line memory 2 stores picture density data for two lines including the noticing pixel. Picture density data in a reference area with the noticing pixel in a center among picture density data stored in the line memory 2 are inputted to an edge likelihood value calculation circuit 3. An emphasizing degree deciding circuit 4 reads picture density data of the noticing pixel from in picture density data stored in the line memory 2, outputs an emphasizing degree 0 when picture density data is not less than a threshold value and outputs the edge likelihood value calculating circuit 3 as an emphasizing degree when picture density data is less than the threshold value.