A robot teaching device, comprising: a teaching point marker display unit configured to display, on a GUI, teaching point markers for marking teaching points in a three-dimensional modeling space in which at least a three-dimensional model of a robot including an end effector and a three-dimensional model of a work piece are arranged, the teaching points serving as target passing points of the end effector; a joined path display unit configured to display, on the GUI, a joined path, which is a path connecting successive points among the teaching points to each other; and a changing point marker display unit configured to display, on the GUI, a changing point marker for marking a point at which a working state of the end effector changes; wherein at least the teaching point markers and the changing point marker are displayed in modes distinguishable from each other; the robot teaching device being further characterized in that it comprises an actual path display unit configured to display, on the GUI, an actual path, which is a path of movement of the end effector; wherein the teaching point marker display unit is configured to dynamically change a display position at which one of the teaching point markers is displayed when a position of one of the teaching points is changed by using the GUI, and wherein the actual path display unit is configured to dynamically change the actual path when the position of the one of the teaching points is changed; and wherein the joined path display unit is configured to display the joined path by following the dynamic change of the display position of one of the teaching point markers as a curve based on what type of move command corresponds to each of the teaching points, which serve as target passing points. a teaching point marker display unit configured to display, on a GUI, teaching point markers for marking teaching points in a three-dimensional modeling space in which at least a three-dimensional model of a robot including an end effector and a three-dimensional model of a work piece are arranged, the teaching points serving as target passing points of the end effector; a joined path display unit configured to display, on the GUI, a joined path, which is a path connecting successive points among the teaching points to each other; and a changing point marker display unit configured to display, on the GUI, a changing point marker for marking a point at which a working state of the end effector changes; wherein at least the teaching point markers and the changing point marker are displayed in modes distinguishable from each other; the robot teaching device being further characterized in that it comprises an actual path display unit configured to display, on the GUI, an actual path, which is a path of movement of the end effector; wherein the teaching point marker display unit is configured to dynamically change a display position at which one of the teaching point markers is displayed when a position of one of the teaching points is changed by using the GUI, and wherein the actual path display unit is configured to dynamically change the actual path when the position of the one of the teaching points is changed; and wherein the joined path display unit is configured to display the joined path by following the dynamic change of the display position of one of the teaching point markers as a curve based on what type of move command corresponds to each of the teaching points, which serve as target passing points.