PROBLEM TO BE SOLVED: To provide a device for obtaining a three-dimensional image of a desired tissue mass by drawing a rotating catheter in a longitudinal direction in order to achieve an optical catheter that rotates for generating an r-φ cross-sectional image, in a clinical field.SOLUTION: The device for transmitting electromagnetic radiation between two fibers separated from each other includes: a first optical fiber 20 and a second optical fiber 30, at least one of which is rotatable； one or more first optical device parts that communicate with one end of at least one of the first and second optical fibers； one or more second device parts that control the positions of the one or more optical device parts to align longitudinal axes of the first and second optical fibers at at least ends thereof； and one or more third device parts that rotate the optical fibers at a speed higher than 10 turns/sec.
