An oxygen measurement device (10A to 10L, 10La to 10Lt), comprising: a urethral catheter (18a to 18j, 18ja to 18jt) including a flexible hollow shaft (22a to 22j, 22ja to 22jt, 22k to 22n); and an oxygen sensor (20a to 20i, 300, 400a to 400c) including an oxygen sensor main body (50a to 50i, 50ha, 50hb, 302, 422a to 422c) capable of detecting oxygen in urine, wherein the shaft (22a to 22j, 22ja to 22jt, 22k to 22n), a urine introduction port (28a to 28k) allowing the urine in a bladder to flow therein, and a urinary passage (74, 416, 454, 474, 486) communicating with the urine introduction port (28a to 28k) to circulate the urine, are disposed, and the oxygen sensor (20a to 20i, 300, and 400a to 400c) is disposed in the urethral catheter (18a to 18j, 18ja to 18jt), wherein the oxygen sensor (20a to 20i, 300, 400a to 400c) includes a transfer portion (52, 304, 424) which is electrically and/or optically connected to the oxygen sensor main body (50a to 50i, 50ha, 50hb, 302, 422a to 422c), a sensor lumen (202, 412, 610, 614) is formed in the shaft (22a to 22j, 22ja to 22jt, 22k to 22n), and the transfer portion (52, 304, 424) is provided in the sensor lumen, characterized in that the oxygen measurement device (10A to 10L, and 10La to 10Lt) further comprising a fixing portion (432a to 432i) fixing the oxygen sensor (20a to 20i, 300, 400a to 400c) to the shaft (22a to 22j, 22ja to 22jt, 22k to 22n), the fixing portion holding the oxygen sensor main body (50a to 50i, 50ha, 50hb, 302, 422a to 422c) such that the oxygen sensor main body (50a to 50i, 50ha, 50hb, 302, 422a to 422c) is in contact with the urine when circulated in the urinary passage (74, 416, 454, 474, 486), the fixing portion (432a to 432i) is liquid-tightly fitted into a distal end portion of the sensor lumen (202, 412, 610, 614) in a state where a distal end of the transfer portion (52, 304, 424) is inserted into the fixing portion (432a to 432i) such that the flow of the urine from the urinary passage to a proximal end side of the fixing portion (432a to 432i) in the sensor lumen (202, 412, 610, 614) is inhibited. a urethral catheter (18a to 18j, 18ja to 18jt) including a flexible hollow shaft (22a to 22j, 22ja to 22jt, 22k to 22n); and an oxygen sensor (20a to 20i, 300, 400a to 400c) including an oxygen sensor main body (50a to 50i, 50ha, 50hb, 302, 422a to 422c) capable of detecting oxygen in urine, wherein the shaft (22a to 22j, 22ja to 22jt, 22k to 22n), a urine introduction port (28a to 28k) allowing the urine in a bladder to flow therein, and a urinary passage (74, 416, 454, 474, 486) communicating with the urine introduction port (28a to 28k) to circulate the urine, are disposed, and the oxygen sensor (20a to 20i, 300, and 400a to 400c) is disposed in the urethral catheter (18a to 18j, 18ja to 18jt), wherein the oxygen sensor (20a to 20i, 300, 400a to 400c) includes a transfer portion (52, 304, 424) which is electrically and/or optically connected to the oxygen sensor main body (50a to 50i, 50ha, 50hb, 302, 422a to 422c), a sensor lumen (202, 412, 610, 614) is formed in the shaft (22a to 22j, 22ja to 22jt, 22k to 22n), and the transfer portion (52, 304, 424) is provided in the sensor lumen, characterized in that the oxygen measurement device (10A to 10L, and 10La to 10Lt) further comprising a fixing portion (432a to 432i) fixing the oxygen sensor (20a to 20i, 300, 400a to 400c) to the shaft (22a to 22j, 22ja to 22jt, 22k to 22n), the fixing portion holding the oxygen sensor main body (50a to 50i, 50ha, 50hb, 302, 422a to 422c) such that the oxygen sensor main body (50a to 50i, 50ha, 50hb, 302, 422a to 422c) is in contact with the urine when circulated in the urinary passage (74, 416, 454, 474, 486), the fixing portion (432a to 432i) is liquid-tightly fitted into a distal end portion of the sensor lumen (202, 412, 610, 614) in a state where a distal end of the transfer portion (52, 304, 424) is inserted into the fixing portion (432a to 432i) such that the flow of the urine from the urinary passage to a proximal end side of the fixing portion (432a to 432i) in the sensor lumen (202, 412, 610, 614) is inhibited.