Abstract: The present invention relates to a precisely actuating member and an image tilting device and a projection system having them, more particularly, to a projection system comprising a precisely actuating member formed in a one-piece unit to permit a precise rotation movement, an image tilting device for increasing the resolution by precisely adjusting the angle of an image, and a projection system having them. The image tilting device according to the preferred aspect of the present invention comprises a casing. The precisely actuating member is housed in the casing to be integrated therewith for precise reciprocation. A driving member contacts to the precisely actuating member for the movement of the actuating member. A light path conversion member is located on the precisely actuating member to convert the light path by a precise movement.