An image processing apparatus includes an integer-part converting unit configured to convert multi-level image data into integer image data by referring to a first conversion table, a threshold setting unit configured to generate matrix data for performing area coverage modulation by referring to the multi-level image data, a decimal-part converting unit configured to convert the multi-level image data into decimal image data by referring to a second conversion table, a level reducing unit configured to reduce levels of the decimal image data by using a threshold generated in the threshold setting unit, an adding unit configured to add the integer image data to the level-reduced decimal image data and outputting a result of addition as gamma conversion image data, and an image processing unit configured to perform image processing on the gamma conversion image data.