A system which can reliably prevent a worker from being caught in a door which is provided on a work machine. The system comprises a work machine which has an operable door, a door drive part which makes the door operate, a door controller which controls the door drive part, a robot which is provided so that at least part can enter and retract from the inside of the work machine when opening the door, and an entry detection part which detects a possibility of a person entering a predetermined zone which includes a range of operation of the robot. The door controller changes a command value to the door drive part which determines the speed of movement of the door when the entry detection part detects that possibility to a second command value which makes the speed of movement decrease.