An image projection apparatus configurable with a coordinate input device and an external apparatus each having interactive input-output capability, the image projection apparatus comprising: an image receiver to receive an image signal from the external apparatus when the external apparatus is coupled or connected to the image projection apparatus, wherein the image projection apparatus adds a pattern information for identifying a position of the coordinate input device to the image signal; an image processor to convert the image signal received by the image receiver to a projection signal; a projection unit to project a projection image on a projection screen using the projection signal; a coordinate calculator to calculate coordinates of a point in the projection image on the projection screen when the point is identified by the coordinate input device and information of coordinates of the identified point is input from the coordinate input device to the image projection apparatus; an interactive communication unit to perform communication of information related to the interactive input-output capability with the coordinate input device, and the external apparatus that outputs the image signal to the image receiver; an operation information converter to convert the coordinates of the point calculated by the coordinate calculator and an operation information of an operation button of the coordinate input device to an operation information used for any one of the image projection apparatus and the external apparatus; a distance calculator to calculate distance between the coordinate input device and the projection screen; and an input-action-reproducing determination unit to determine whether movement of coordinates of the point on the projection screen identified by the coordinate input device is to be reproduced on the projection screen depending on the distance calculated by the distance calculator; characterized in that: when it is determined that the coordinate input device is not being contacted with the projection screen, theinput-action-reproducing determination unit is configured to compare the coordinates of the point currently detected and the coordinates of the point previously detected to calculate a moved length of the coordinates, and determine whether the calculated moved length of coordinates exceeds a threshold, wherein when it is determined that the moved length of coordinates does not exceed the threshold, the input-action-reproducing determination unit is configured to determine not to transmit the operation information to the external apparatus. an image receiver to receive an image signal from the external apparatus when the external apparatus is coupled or connected to the image projection apparatus, wherein the image projection apparatus adds a pattern information for identifying a position of the coordinate input device to the image signal; an image processor to convert the image signal received by the image receiver to a projection signal; a projection unit to project a projection image on a projection screen using the projection signal; a coordinate calculator to calculate coordinates of a point in the projection image on the projection screen when the point is identified by the coordinate input device and information of coordinates of the identified point is input from the coordinate input device to the image projection apparatus; an interactive communication unit to perform communication of information related to the interactive input-output capability with the coordinate input device, and the external apparatus that outputs the image signal to the image receiver; an operation information converter to convert the coordinates of the point calculated by the coordinate calculator and an operation information of an operation button of the coordinate input device to an operation information used for any one of the image projection apparatus and the external apparatus; a distance calculator to calculate distance between the coordinate input device and the projection screen; and an input-action-reproducing determination unit to determine whether movement of coordinates of the point on the projection screen identified by the coordinate input device is to be reproduced on the projection screen depending on the distance calculated by the distance calculator; characterized in that: when it is determined that the coordinate input device is not being contacted with the projection screen, theinput-action-reproducing determination unit is configured to compare the coordinates of the point currently detected and the coordinates of the point previously detected to calculate a moved length of the coordinates, and determine whether the calculated moved length of coordinates exceeds a threshold, wherein when it is determined that the moved length of coordinates does not exceed the threshold, the input-action-reproducing determination unit is configured to determine not to transmit the operation information to the external apparatus. when it is determined that the coordinate input device is not being contacted with the projection screen, theinput-action-reproducing determination unit is configured to compare the coordinates of the point currently detected and the coordinates of the point previously detected to calculate a moved length of the coordinates, and determine whether the calculated moved length of coordinates exceeds a threshold, wherein when it is determined that the moved length of coordinates does not exceed the threshold, the input-action-reproducing determination unit is configured to determine not to transmit the operation information to the external apparatus.