An endoscope 1 includes: an insertion portion 10 that includes a distal end portion 11 in which an image sensor 11A and a laser diode 11B are disposed, a bending portion 12 for changing a direction of the distal end portion 11, and a flexible portion 13 having flexibility and extended from the bending portion 12, the image sensor outputting an image pickup signal, the laser diode converting the image pickup signal into an optical signal an operation portion 20 that is disposed on a proximal end side of the insertion portion 10 an universal cord 30 that is extended from the operation portion 20 a connector 40 that is disposed on a proximal end side of the universal cord 30 an optical fiber 50 that is inserted through the insertion portion and transmits the optical signal and a stress relief portion 51 that changes an effective length L1 of the optical fiber 50 in accordance with a stress applied to the optical fiber 50, the effective length being a length of the optical fiber along an insertion direction thereof.
