In one embodiment, an image analysis device (65) includes an acquisition unit (66) and an analysis unit (67). The acquisition unit acquires image data of a plurality of images of an imaging region of an object respectively imaged by magnetic resonance imaging before and after administration of contrast medium. The analysis unit calculates an estimated value of concentration of contrast medium per unit volume including air region by using a coefficient based on the image data before administration of contrast medium, in accordance with the image data of a plurality of images and a value related to relaxation rate or relaxation time before and after administration of contrast medium.