An analysis system comprises an endoscope 10 insertable into the vessel and a Raman analysis apparatus 40. An insert cable 54 of the Raman analysis apparatus 40 is inserted into a channel 10a of the endoscope 10. An excitation optical fiber 60 and a bundle 70A of a plural number of light receivingoptical fibers 70 are received in the insert cable 54. A transparent small piece 63 having a film-like excitation optical filter 64 is abutted against the distal end of the fiber 60. A transparent plate 71 having a film-like light reciving optical filter 72 is abutted against the distal end of fibers bundle 70A. The plate 71 has a center hole 71a and the piece 63 is fitted into the hole 71a.