An illumination pen includes a hollow pen holder having a receiving cavity and a lower light transmissible body, a writer device and an actuator. The writer device includes a pen core, an illumination device including a battery and an illuminator. The actuator includes a rotor rotatably provided on the pen holder, and a driving member including a conductive arm and a pushing arm. When the rotor is rotated at a clockwise direction, the conductive arm is driven to electrically connect with the illuminator so as to light it up, when the rotor is rotated at a counter-clockwise direction, the pushing arm is driven towards the illuminator to move the writing tip of the pen core out of the bottom opening of the pen holder.