PROBLEM TO BE SOLVED: To reduce the blurring of an image.SOLUTION: The area Rc of a circle in k space is divided into four in a circumferential direction CD to define four areas Rto R. Data Dto Dof the respective areas Rto Rare subjected to reverse Fourier conversion to obtain image data DIto DI. After obtaining the image data DIto DIthe respective pixels of the image data DIto DIare shifted &Dgrxto &Dgrxin an x direction and &Dgryto &Dgryin a y direction to obtain image data DI to DI. After obtaining the image data DI to DI, the complex sums of the same is obtained to obtain final image data DI.