1. A magnetic resonance imaging apparatus comprising: an imaging unit configured to acquire frames of diffusion weighted image data corresponding to different b-values by diffusion weighted imaging with applying MPG pulses corresponding to the different b-values of which application axes are same; and a strain correction unit configured to calculate a strain correction coefficient for diffusion weighted image data to be a target of a strain correction based on diffusion weighted image data corresponding to a b-value different from a b-value corresponding to the diffusion weighted image data to be the target of the strain correction among the frames of the diffusion weighted image data to generate image data after the strain correction by the strain correction of the diffusion weighted image data to be the target of the strain correction using the calculated strain correction coefficient.