The utility model discloses a portable CO concentration detection device which comprises an outer tube, a connecting tube is arranged at one end in the outer tube, a
threaded rod is inserted into the connecting tube and the outer tube, an internal thread matched with the
threaded rod is arranged at one end, far away from the outer tube, of the connecting tube, and one end, far away from the outer tube, of the
threaded rod is fixedly connected with a connecting plate. The end, away from the outer
pipe, of the connecting plate is fixedly connected with the shell, an air inlet is formed in the side wall of the side, away from the connecting plate, of the shell, a fan is arranged on the side, located in the air inlet, of the shell, a
CO detection sensor is arranged on the side, close to the fan, in the shell, and a partition plate is arranged on the side, away from the air inlet, in the shell. A
lithium battery is arranged on the side, away from the
CO detection sensor, of the partition plate. The detection device is simple in structure, convenient to operate and good in detection effect, the length is convenient to adjust, narrow areas and high positions can be detected, and the use convenience of the detection device is effectively improved.