Disclosed are a collimator for reducing noise of a scanned image and an imaging catheter system comprising the same. The disclosed noise attenuation collimator comprises: a transparent tube having a diameter larger than a cladding diameter of double-clad fiber, wherein a coatingless region of the double-clad fiber is inserted into the transparent tube; and a first resin layer which is applied to an exterior of the transparent tube and has a refractive index lower than the refractive index of the transparent tube.