In an image calibration device 10, a calibration pattern is projected onto a screen 4 from each projector 3 under control of a personal computer or other calibration device 10a, pictures are taken by a digital camera or other image pick-up device 11, and the results are supplied to the calibration device 10a. The calibration device 10a uses the supplied picture data to calculate parameters in order to perform picture positioning, color adjustment, brightness adjustment and other adjustments and corrections, and based on the calculation results transforms the original picture data, generates and supplies signals indicating projection conditions to each of the projectors 3, and performs image calibration control of the pictures projected by each projector 3. Here at the time of taking pictures, by installing on the image pick-up device 11 a shielding member 12 formed into a tetragonal pyramid shape, the light-receiving part of the image pick-up device 11 and the screen are completely shielded from ambient external light. By this means, the measurement precision of the image pick-up device 11 is improved, and accurate and reliable image calibration is performed.