An endoscope 1 includes: an insertion portion 2 a distal end face 14a that can receive light from an observed body a detection fiber 14 that transmits light received by the distal end face 14a an opening 17 that opens near the distal end face 14a a treatment instrument insertion channel 16 inserted into the insertion portion 2 an endoscope main body portion 3 consecutively connected with the insertion portion 2 a treatment instrument insertion port 7 that is provided on the endoscope main body portion 3 and that includes an opening communicating with the treatment instrument insertion channel 16 an external detection fiber 10 that is provided on the endoscope main body portion 3 and that can guide light between outside and inside of the endoscope main body portion 3 and a merging portion 15 that is provided inside of the endoscope main body portion 3 and that merges the light transmitted by the detection fiber 14 and the light guided by the external detection fiber 10.
