PULSE OXIMETER

PROBLEM TO BE SOLVED: To provide a pulse oximeter which is turned to a ring type in order to improve a fit property of a finger and is capable of finger recognition even under sunlight.SOLUTION: In a pulse oximeter 1 including a measuring device body 3 which stores a power source 80 and a control board loaded with an electronic circuit driven by the power source 80 and has a display part 2 for displaying information processed by the electronic circuit, and a detection part 4 mounted on the measuring device body 3, the detection part 4 includes: a light emitting side arm 5 which extends from the measuring device body 3 to one side and brings a light emitting means 6 into contact with one side part of a finger of a subject; a light receiving side arm 7 which extends from the measuring device body 3 to the other side and brings a light receiving means 8 into contact with the other side of the finger of the subject; and belt parts 9 and 10 which extend from one of the light emitting side arm 5 and the light receiving side arm 7 to the other side, for fixing the measuring device body 3 to the root of the finger of the subject or a second finger joint part.