A calibration information calculation unit (540) calculates a plurality of candidates of first coordinate transformation information using a plurality of candidates of second coordinate transformation information, a sensor measured value, and the position and orientation of a video camera (100) on the world coordinate system. The calibration information calculation unit (540) then calculates a piece of first coordinate transformation information by combining the plurality of calculated candidates. Then, the calibration information calculation unit (540) makes iterative calculations for correcting calibration information using a candidate of the second coordinate transformation information and the first coordinate transformation information as initial values of the calibration information.