A probe is configured to be detachably attached to a rotary junction unit of the imaging apparatus for diagnosis, and is inserted into a body lumen. The probe includes a plurality of transmitting and receiving units that obtain tomographic images by transmitting and receiving signals inside the body lumen and a drive shaft that receives a rotary-drive force from the rotary junction unit and rotates the plurality of transmitting and receiving units. Then, the plurality of transmitting and receiving units are respectively disposed along axial directions by adjusting angles with respect to directions orthogonal to the axial directions so that the signals are transmitted in directions identical to the directions orthogonal to the axial directions of the rotation among directions to a distal side of the probe and a proximal side of the probe.
