A robot teaching device is suitable for being signal connected to a controller used to control a robot, and includes: a connecting base which includes an enable switch and a first connector, and is connected to the controller by a transmission wire; a motion device which is removably disposed in the connecting base, and includes a second connector connected to the first connector, and a touch screen for displaying plural virtual keys. The motion device will be wirelessly signal connected to the controller, when it is removed from the connecting base, and the touch screen will display the virtual keys. When the motion device is inserted in the connecting base, and the enable switch is not pressed, the first and second connectors will be connected, and the virtual keys will be switched off. The virtual keys will be switched on after the enable switch is kept being pressed.