A camera calibrating apparatus to be operative in combination with an imaging device which includes a housing unit and an optical section supported by said housing unit to obtain image information through said optical section, and adapted to calibrate position information of said optical section, comprising: first housing position information storing means for storing first housing position information indicative of a position of said housing unit in a first coordinate system, the first coordinate system being defined in a first working space; second housing position information storing means for storing second housing position information indicative of a position of said housing unit in a second coordinate system in which a calibrating marker is located, the second coordinate system being defined in a second working space; first optical position information producing means for producing first optical position information indicative of a position of said optical section in said first coordinate system on the basis of said image information obtained by said imaging device in said first coordinate system; first optical position information storing means for storing said first optical position information produced by said first optical position information producing means; second optical position information producing means for producing second optical position information indicative of a position of said optical section to said second coordinate system from said second housing position information stored by said second housing position information storing means on the basis of said first housing position information stored by said first housing position information storing means and said first optical position information stored by said first optical position information storing means; second optical position information storing means for storing said second optical position information produced by said second optical position information producing means; and calibrating means for calibrating said second optical position information stored by said second optical position information storing means on the basis of said image information of said calibrating marker obtained by said imaging device in said second coordinate system, wherein the second optical position information is calibrated in consideration with only the rotational displacement of the optical section 112. first housing position information storing means for storing first housing position information indicative of a position of said housing unit in a first coordinate system, the first coordinate system being defined in a first working space; second housing position information storing means for storing second housing position information indicative of a position of said housing unit in a second coordinate system in which a calibrating marker is located, the second coordinate system being defined in a second working space; first optical position information producing means for producing first optical position information indicative of a position of said optical section in said first coordinate system on the basis of said image information obtained by said imaging device in said first coordinate system; first optical position information storing means for storing said first optical position information produced by said first optical position information producing means; second optical position information producing means for producing second optical position information indicative of a position of said optical section to said second coordinate system from said second housing position information stored by said second housing position information storing means on the basis of said first housing position information stored by said first housing position information storing means and said first optical position information stored by said first optical position information storing means; second optical position information storing means for storing said second optical position information produced by said second optical position information producing means; and calibrating means for calibrating said second optical position information stored by said second optical position information storing means on the basis of said image information of said calibrating marker obtained by said imaging device in said second coordinate system, wherein the second optical position information is calibrated in consideration with only the rotational displacement of the optical section 112.