A work management system includes a generator attached to a structure body that is provided to a transmission case of a working machine, configured to be driven by power transmitted from a PTO shaft, and configured to transmit power to a working device provided in the working machine, an information obtaining portion configured to obtain operation information representing operation of the working device that is activated by the power from the generator, a work management portion configured to manage working of the working device based on the operation information obtained by the information obtaining portion, and a controller portion configured to control the working device based on the operation information obtained by the information obtaining portion.