Provided is a magnetic resonance imaging apparatus capable of highly precisely detecting and compensating body motions within a short processing time during radial scanning. The magnetic resonance imaging apparatus includes a control unit that applies radiofrequency magnetic fields and magnetic field gradients to a subject lying down in a static magnetic field and that detects magnetic resonance signals generated from the subject, and an arithmetic unit that handles the signals. The arithmetic unit performs subject's body motion detection in an image space, uses an image, which is reconstructed using the low-frequency portion of the k-space data of the image, as criterial data, produces templates by moving the criterial data in advance by predetermined magnitudes of rotations and predetermined magnitudes of translations, and uses the produced templates to perform the body motion detection.