Multi-valued image data corresponding to a pixel area is divided into the first scanning multi-valued data, first and second scanning common multi-valued data, and second scanning multi-valued data. A quantization processing is executed on each of the multi-valued data to generate first scanning quantized data, first and second scanning common quantized data, and second scanning quantized data. After that, these pieces of quantized data are combined for each scanning to generate first scanning combined quantized data and second scanning combined quantized data. According to this, the amount of pixels where dots are both recorded by performing a scanning by plural times (the amount of overlapping dots) is controlled, and while suppressing the image density variations, the granularity is held to a low level.