1. An image processing apparatus configured to rasterize an object into a bitmap using a first memory and a second memory which can be accessed quicker than the first memory, the image processing apparatus comprising: an extraction unit configured to extract a plurality of objects to be rasterized on the second memory from a plurality of the objects; and a first combination unit configured to combine a plurality of objects which can be rasterized within capacity of the second memory from among the plurality of objects extracted by the extraction unit into an object.