An imaging apparatus for diagnosis is connected detachably with a probe having a first transmitting and receiving unit repeating electric signal transmission and reception and a second transmitting and receiving unit repeating optical signal transmission and reception, obtains a reflected signal inside a body cavity or lumen from the first or second transmitting and receiving unit by rotationally operating the first and the second transmitting and receiving units inside the body cavity, and can generate a tomographic image inside the body cavity, wherein the apparatus includes an electric rotary connector carrying out transmission of the electric signal while rotationally operating the first and second transmitting and receiving units； and an optical rotary connector carrying out transmission of the optical signal, the electric rotary connector includes a metal surface on the rotational drive unit side and a brush on the fixed unit side that is operable between contact and non-contact positions.
