An inkjet printing apparatus for printing an image on a surface of a recording medium, comprising: a head having a plurality of nozzles arranged in a main scanning direction, said plurality of nozzles ejecting ink to a surface of a recording medium; a transport mechanism that transports a recording medium relative to said head in a sub-scanning direction orthogonal to said main scanning direction; an image capturing part that captures an image of a surface of a recording medium at an image capturing position located downstream of said head in said sub-scanning direction; a detector that detects an amount of displacement in position of a recording medium in said main scanning direction at said image capturing position; and a controller connected to said head, said transport mechanism, said image capturing part, and said detector, said controller including: a chart print instruction part that controls and causes said head and said transport mechanism to print a shading chart whose density changes in a stepwise fashion in said sub-scanning direction on a recording medium; an image acquisition part that controls and causes said image capturing part to acquire a plurality of captured images for a region of the same density of said shading chart; an ultra-resolution processing part that generates one super-resolution image with a higher resolution than said plurality of captured images on the basis of said plurality of captured images acquired by said image capturing part, and amounts of displacement in position of a recording medium in said main scanning direction acquired by said detector; and a correction amount calculation part that calculates a variable-density correction amount for each of said plurality of nozzles on the basis of said ultra-resolution image. a head having a plurality of nozzles arranged in a main scanning direction, said plurality of nozzles ejecting ink to a surface of a recording medium; a transport mechanism that transports a recording medium relative to said head in a sub-scanning direction orthogonal to said main scanning direction; an image capturing part that captures an image of a surface of a recording medium at an image capturing position located downstream of said head in said sub-scanning direction; a detector that detects an amount of displacement in position of a recording medium in said main scanning direction at said image capturing position; and a controller connected to said head, said transport mechanism, said image capturing part, and said detector, said controller including: a chart print instruction part that controls and causes said head and said transport mechanism to print a shading chart whose density changes in a stepwise fashion in said sub-scanning direction on a recording medium; an image acquisition part that controls and causes said image capturing part to acquire a plurality of captured images for a region of the same density of said shading chart; an ultra-resolution processing part that generates one super-resolution image with a higher resolution than said plurality of captured images on the basis of said plurality of captured images acquired by said image capturing part, and amounts of displacement in position of a recording medium in said main scanning direction acquired by said detector; and a correction amount calculation part that calculates a variable-density correction amount for each of said plurality of nozzles on the basis of said ultra-resolution image. a chart print instruction part that controls and causes said head and said transport mechanism to print a shading chart whose density changes in a stepwise fashion in said sub-scanning direction on a recording medium; an image acquisition part that controls and causes said image capturing part to acquire a plurality of captured images for a region of the same density of said shading chart; an ultra-resolution processing part that generates one super-resolution image with a higher resolution than said plurality of captured images on the basis of said plurality of captured images acquired by said image capturing part, and amounts of displacement in position of a recording medium in said main scanning direction acquired by said detector; and a correction amount calculation part that calculates a variable-density correction amount for each of said plurality of nozzles on the basis of said ultra-resolution image.