A robot simulation apparatus which simulates a motion of a robot equipped with an end effector on a display screen, having: a position specifying portion, which, along with a three-dimensional model of the robot and three-dimensional models of a workpiece and a peripheral device displayed in prescribed positions relative to each other on the display screen, specifies a two-dimensional position on the screen to designate a prescribed position at a destination as a target to which the end effector, moving relative to the workpiece and the peripheral device, is to be moved; a position data acquiring portion, which converts data representing the two-dimensional position specified by the position specifying portion into data representing a three-dimensional position and thereby acquires the three-dimensional position of the destination; a shape data acquiring portion, which acquires shape data of the workpiece based on the three-dimensional position acquired by the position data acquiring portion; and a position/orientation computing portion, which based on the three-dimensional position and the shape data, computes the three-dimensional position and three-dimensional orientation of the robot.