1. An object determining device comprising: imaging means for obtaining an image of the object; likelihood value calculating means for calculating a first likelihood value for the object shown in the image obtained by the imaging means by use of the image obtained by the imaging means and a machine learning system trained so as to respond to a sample image of a sample object that is wearing a covering and for calculating a second likelihood value for the object shown in the image obtained by the imaging means by use of the image obtained by the imaging means and a machine learning system trained so as to respond to a sample image of a sample object that is not wearing a covering, the first likelihood value indicating a level of likelihood that the object is wearing the covering and the second likelihood value indicating a level of likelihood that the object is not wearing the covering; and determining means for determining whether or not the object, shown in the image obtained by the imaging means, is wearing a covering, on the basis of a ratio between the first likelihood value and the second likelihood value calculated by the likelihood value calculating means.