According to one embodiment, a compression plate compresses a breast of a subject with the breast between the compression plate and an imaging plane of an imaging table. The compression plate including a compression face and a chest wall face. The compression face is configured to compress the breast to the imaging table. The chest wall face is configured continuously from the compression face to be in contact with a chest wall of the subject during X-ray imaging. The chest wall face includes a second region which is in contact with the chest wall of the subject, and the second region has surface roughness which is greater than that of a first region of the compression face, which is opposed to the imaging table.
