Abstract: A method for managing working hours using post-factum fingerprint registration according to one embodiment of the present invention comprises the steps of: acquiring the working hours of a user in response to an ID inputted from the user and each of a plurality of fingerprint images corresponding to the ID; storing the ID, the fingerprint images, and the working hours; selecting the post-factum registration fingerprint image for ID from the fingerprint images; and comparing the post-factum registration fingerprint image with the remaining fingerprint images.