At the time of superimposing and aligning a stained image and a mass spectrometric (MS) image obtained for the same sample, an image display processor displays, on the superimposed images, grid lines (62) at the spacing corresponding to an operation of a grid spacing adjustment slider (63). When an operator depresses an image deformation range “SET” button (64), specifies an arbitrary area on the superimposed images with a mouse, and then depresses a “SELECT” button (65), an image deformation range specification receiving section determines an image deformation range. When the operator selects an intersection (grid point) of the grid lines (62) within the image deformation range and performs an operation of moving the intersection point to an arbitrary position, an image deformation processor deforms an image included in the image deformation range in accordance with the operation. The image deformation range can be set irrespective of the grid-line spacing, so that it is possible to perform accurate image deformation in accordance with the amount and range of deformation for each site on the image, and improve work efficiency.