The utility model discloses a carbon dioxide measuring apparatu, include: a housing, sealed carbon dioxide detection space is injectd by the casing, air carbon dioxide sensor, the air carbon dioxide sensor settings be in in the carbon dioxide detection space, a data processor, data processor with air carbon dioxide sensor links to each other, a display screen, the display screen inlays to be established on the casing, and with data processor links to each other, the elasticity wrist strap, the elasticity wrist strap with the casing links to each other, constant temperature heating spare, constant temperature heating spare sets up the casing is inboard, and sealing ring, seal annular sleeved establishes on the casing. This carbon dioxide measuring apparatu has small, advantages such as wearing, low price and non -invasive detection with oneself.