1. An image reconstruction device which generates an iteratively reconstructed image by performing a repeated calculation on the basis of a difference between calculated projection data and measured projection data, the calculated projection data being obtained by performing a forward projection calculation on a reconstructed image which is reconstructed based on the measured projection data, the image reconstruction device comprising: an input section to which an image quality parameter which is considered to be important by an operator s input; a weight calculation section that calculates a weighting coefficient on the basis of the image quality parameter; and a repeated calculation section that performs a repeated calculation on the basis of a value obtained by weighting and adding a pixel value obtained in the previous iteration to a pixel value obtained from now using the weighting coefficient.