High-speed optical delay generating method by rotation reflector in optical coherence tomography and optical coherence tomography device

A high-speed optical delay generating method by a rotation reflector in optical coherence tomography, capable of providing a sectional picture with a sufficiently long depth-direction (Z direction) scanning distance, and an optical coherence tomography device therefor are provided. The device comprises a low-coherence light source ( 1 ), a half mirror ( 2 ) for splitting light from the low-coherence light source ( 1 ) into two, that is, into object light towards an object (A) to be examined and reference light, a light delay mechanism ( 3 ) for delaying the reference light by means of a rotation reflector ( 12 ), a fixed mirror ( 4 ) for reflecting/returning the reference light from the light delay mechanism ( 3 ), the half-mirror ( 2 ) for combining the object light returning from the object (A) to be examined with the reference light returning from the light delay mechanism, and a light detector ( 11 ) for detecting interference light including a heterodyne interference beat signal combined at the half mirror ( 2 ).