Abstract: An interactive projection system includes a pointing element having a first end portion used for a writing mode, and a second end portion used for an erasing mode, a projection section projecting an image on a screen surface in accordance with an input operation using the pointing element, a first camera taking an image of the pointing element, a second camera disposed at a different position from a position of the first camera and taking an image of the pointing element, a detection section adapted to detect a position on the screen surface pointed by the pointing element based on the first camera image and the second camera image, and a determination section adapted to determine whether an operation mode is the writing mode or the erasing mode based on a matching check between the first camera image or the second camera image and a template image.