A robot system includes a robot and a robot controller including a drive unit, a memory that stores an arm-occupied region and a movement-forbidden region, a target position calculation unit that outputs a target position of a tool or a workpiece, a movement-forbidden region entry monitoring unit that checks whether the arm-occupied region based on the target position enters the movement-forbidden region and outputs a stop request if it is checked that the arm-occupied region enters the movement-forbidden region, and a predicted-coasting-position calculating unit that calculates a predicted coasting position of each axis and a coasting position of the tool or the workpiece in the case that the robot is urgently stopped. The movement-forbidden region entry monitoring unit checks whether the arm-occupied region at the coasting position enters the movement-forbidden region and outputs another stop request if it is checked that the arm-occupied region enters the movement-forbidden region.