To efficiently record various data necessary for vehicle operation control and to facilitate data processing by equipping respectively specific means such as a time chart recording means, an work event recording means and a record managing means.

A work event recording function part 2A generates work event data showing the kind of work event when the work event is generated. A time chart recording function part 2A periodically generates time chart data showing a vehicle operation state based on an operation state detecting means detecting the operation state of the vehicle. A record control function part 2C makes time chart data and work event data sent from each function part 2A a recorde and records it as a recording record in a data recording area 2D by giving an attribute showing the characteristic of each data. A inquiry function part 2E is provided with a function taking out a desired recording record from the data recording area 2D.