A catheter device for laser ablation comprising a detection system, the detection system comprising: an optical fiber; at least one light source (LD1a, LD1b) configured to output a plurality of test beams input to a proximal end portion side of the optical fiber and having different wavelengths and providing different bending losses of the optical fiber; at least one reflector that reflects each of the test beams (TL1, TL2) propagating through the optical fiber, on a distal end portion side of the optical fiber; a plurality of light receiving units (PD2a, PD2b) configured to receive a plurality of reflected beams (RL1, RL2) each being a beam reflected by the at least one reflector, on the proximal end portion side; and a determination unit configured to compare, based on information about the reflected beams (RL1, RL2) at the plurality of light receiving units (PD2a, PD2b), the information about the reflected beams (RL1, RL2) with reference set values, wherein the information about the reflected beams (RL1, RL2) includes a received light intensities of the reflected beams (RL1, RL2) at the light receiving units (PD2a, PD2b), and the reference set values are thresholds of the received light intensities, and the determination unit being configured to determine whether the optical fiber is bent or broken based on the received light intensities of the reflected beams (RL1, RL2), the determination unit being configured to determine that the optical fiber is broken, when a received light intensity of a first reflected beam, of the plurality of reflected beams (RL1, RL2), is not more than a first threshold, the first reflected beam being a reflected beam from a first test beam, determine that the optical fiber is not broken, when the received light intensity of the first reflected beam is larger than the first threshold, and determine that the optical fiber is bent with an amount of bending not less than a predetermined amount of bending, when the received light intensity of the first reflected beam is larger than the first threshold and a received light intensity of a second reflected beam, of the plurality of reflected beams (RL1, RL2), is not more than a second threshold, the second reflected beam being a reflected beam from a second test beam providing a larger bending loss in the optical fiber than the first test beam, the catheter device further comprising a catheter body into which at least a part of the optical fiber is inserted. an optical fiber; at least one light source (LD1a, LD1b) configured to output a plurality of test beams input to a proximal end portion side of the optical fiber and having different wavelengths and providing different bending losses of the optical fiber; at least one reflector that reflects each of the test beams (TL1, TL2) propagating through the optical fiber, on a distal end portion side of the optical fiber; a plurality of light receiving units (PD2a, PD2b) configured to receive a plurality of reflected beams (RL1, RL2) each being a beam reflected by the at least one reflector, on the proximal end portion side; and a determination unit configured to compare, based on information about the reflected beams (RL1, RL2) at the plurality of light receiving units (PD2a, PD2b), the information about the reflected beams (RL1, RL2) with reference set values, wherein the information about the reflected beams (RL1, RL2) includes a received light intensities of the reflected beams (RL1, RL2) at the light receiving units (PD2a, PD2b), and the reference set values are thresholds of the received light intensities, and the determination unit being configured to determine whether the optical fiber is bent or broken based on the received light intensities of the reflected beams (RL1, RL2), the determination unit being configured to determine that the optical fiber is broken, when a received light intensity of a first reflected beam, of the plurality of reflected beams (RL1, RL2), is not more than a first threshold, the first reflected beam being a reflected beam from a first test beam, determine that the optical fiber is not broken, when the received light intensity of the first reflected beam is larger than the first threshold, and determine that the optical fiber is bent with an amount of bending not less than a predetermined amount of bending, when the received light intensity of the first reflected beam is larger than the first threshold and a received light intensity of a second reflected beam, of the plurality of reflected beams (RL1, RL2), is not more than a second threshold, the second reflected beam being a reflected beam from a second test beam providing a larger bending loss in the optical fiber than the first test beam, the catheter device further comprising a catheter body into which at least a part of the optical fiber is inserted.