A mammography device 1 is an apparatus for acquiring internal information of a breast B of an examinee A by radiating light to the breast B and detecting the diffused light, and includes a container 3 configured to surround the breast B and a plurality of optical fibers 11 attached to be directed inward in the container 3 and configured to perform radiation and detection of light. The container 3 has a base member 30 having an opening 30a, a plurality of annular members 40 continuously disposed to come in communication with the opening 30a, and a bottom member 50 disposed inside the annular member 40 spaced the farthest distance from the base member 30. The annular members 40 and the bottom member 50 are configured to relatively displace the adjacent annular member 40 on the side of the base member 30 or the base member 30 in a communication direction. Some of the plurality of optical fibers 11 is attached to the plurality of annular members 40.
