A work management system comprising: 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 ; and a motor configured to be driven by the power from the generator , wherein the working device has a rotor to be turned by power from the motor to spread a spread substance, and wherein the controller portion controls a rotating speed of the rotor based on the operation information; characterized in that the work management system comprises: a posture detector device configured to detect a posture of the working device ; and a posture adjuster mechanism configured to adjust the posture of the working device based on the posture detected by the posture detector device , wherein the information obtaining portion obtains, as the operation information, posture information relating to the posture of the working device detected by the posture detector device , and wherein the controller portion controls the rotating speed of the rotor based on the posture information obtained by the information obtaining portion . 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 ; and a motor configured to be driven by the power from the generator , wherein the working device has a rotor to be turned by power from the motor to spread a spread substance, and wherein the controller portion controls a rotating speed of the rotor based on the operation information; a posture detector device configured to detect a posture of the working device ; and a posture adjuster mechanism configured to adjust the posture of the working device based on the posture detected by the posture detector device , wherein the information obtaining portion obtains, as the operation information, posture information relating to the posture of the working device detected by the posture detector device , and wherein the controller portion controls the rotating speed of the rotor based on the posture information obtained by the information obtaining portion . <EOS>