1. A store system comprising: an image output section configured to output an image picked up by an image pickup section; an object recognizing section configured to recognize a specific object by reading a feature value of the output image; a similarity determining section configured to calculate similarity indicating to which degree the recognized object is similar to a reference image of the object determined in advance and determine whether the calculated similarity exceeds a threshold set in advance; and a defective informing section configured to inform, if the similarity determining section determines that the calculated similarity does not exceed the threshold set in advance, that the object is not recognized as a regular commodity.