A robot control device according to an aspect of the invention is a robot control device that controls a robot on the basis of a simulation result of a simulation device that performs a simulation of operation of a virtual robot on a virtual space. In the simulation, a first region and a second region located on an inside of the first region can be set on the virtual space. In the case where the virtual robot operates, when a specific portion of the virtual robot intrudes into the first region, operating speed of the virtual robot is limited. When the specific portion of the virtual robot intrudes into the second region, the operation of the virtual robot stops or the virtual robot retracts from the second region.