1. A biometric information obtaining apparatus, comprising: image obtaining means which captures a plurality of successive partial images of successive portions of biometric information from an object moving relative to said image obtaining means while keeping contact with an image capturing surface; characteristic extracting means which obtains, from an individual partial image obtained by said image obtaining means, a characteristic contained in said individual partial image and a position of the characteristic; relative position information detecting means which detects relative position information of two or more of the partial images, obtained by said image obtaining means, based on the characteristic contained in a region in which said two or more partial images overlap; and correcting means which obtains a distance between same characteristics existing in a region in which the two or more partial images overlap based on the relative position information detected by said relative position information detecting means and on the position of the characteristic in the individual partial image and then calculates an amount of distortion of the characteristic caused by deformation of the object resulting from a frictional force accompanying the contact movement of the object based on the distance, and which corrects the position of the characteristic in the individual partial image based on the calculated distortion amount so as to eliminate the distortion caused by deformation of the object resulting from the frictional force when said image obtaining means is capturing the plurality of successive partial images.