1. A target object detecting method for detecting from a digital image a predetermined target object included therein, said method comprising the steps of: using a computer to carry out the steps of: performing a standard target object detecting process for detecting the predetermined target object having a standard characteristic on the digital image; and performing a characteristic target object detecting process for detecting the predetermined target object having a predetermined specific characteristic on the digital image from which said predetermined target object has not been detected by said standard target object detecting process, wherein a plurality of characteristic target object detecting processes, each corresponding to each of the predetermined specific characteristics that differ from each other, are performed sequentially until said predetermined target object has been detected, and the predetermined specific characteristics include an eyeglassed face, a whiskered face or a uniquely hairstyled face.