To provide an image processor which can always provide high-quality recorded images.

A storing means 204 stores the information (a plurality of pattern information on the use/nonuse of each recording material in a plurality of recording elements respectively installed to recording heads, and reference information used for deciding pattern information used at the time of recording objective picture elements correlated with the pattern information) 204, which is used at the time of recording an objective image on a recording medium one picture element by one picture element by means of the recording elements. A correcting means 207 corrects the information 204 stored in the storing means 204 based on the measured result of the density of a prescribed image (test pattern) prerecorded on the recording medium.