PURPOSE: To provide the working hour managing device which can execute management of elaborate working hour in each job site level, and also, can execute centralized control of the working hour by a miniature device.

CONSTITUTION: The device is constituted by providing an input means 2 for inputting arbitrarily target working hour, a timer 9 for counting actual working hour of the work, a comparing arithmetic means 7 for comparing and calculating time counting hours and actual workhours, a data display means 3, an alarm output means 4, and a recording means 5. Also, this device is provided with plural working hour managing devices 12, 13... N provided with a transmitting/receiving control part of data, a data centralized control device 15 for receiving the transmission from the working hour managing device and executing concentrically the data management, and also, transmitting necessary data to the working hour managing device, and a recording means 5 for recording the data processed by the data centralized control device 15.