When conveying tables for conveying the printing medium are selected to perform interlace printing, the occurrence of unevenness in an image which results from switching of the tables is prevented. It is determined whether a phase of the conveying table is a transfer inhibition phase in transfer to a printing area. In the case of the transfer inhibition phase, the switching is not made to a new table, but the previously used table is used. Thus, the switching can be made to a conveying table so as not to make a shift amount +1/2N or −1/N continue. Consequently, it is possible to prevent the occurrence of unevenness in an image which is caused by 1/N deviation of a printing position in a sub-scanning direction with regard to print data at the time of transfer from a rear end area to the normal area or the normal area to the rear end area.