Disclosed an image forming apparatus including: a data receiving section; a memory section comprising a shared storage area; an analysis section to generate an intermediate data from the page-description language; a rasterizing section to generate the bitmap data from the intermediate data and to release an storage area; and a print control section to allow a printing section to perform printing, and to release an storage area; wherein a rasterizing section comprises a judgment section to judge whether or not the following condition expression is satisfied when the shared storage area is run out, (number of rasterized pages)−(number of pages whose memory area saved for storing the bitmap data has been released))>0 when the condition expression is satisfied, the rasterizing section holds a processing until the shared storage area opens, and when the condition expression is not satisfied, a process for a memory-full error is performed.