Provided are: a respiration measuring conversion device for respirometers which can easily be attached to an existing mechanical respirometer and which digitizes measured values a respirometer equipped with the respiration measuring conversion device and a respiration measuring method. The present invention relates to a respiration measuring conversion device 20 for respirometers, the respiration measuring conversion device 20 converting respiratory scales indicating expired volume or expiratory pressure into electrical signals to measure respiration by being attached to a respirometer that includes a cylinder, a piston that moves inside the cylinder 2a, and a marker 6 that moves along with the movement of the piston and indicates an upper most position of the piston. The respiration measuring conversion device 20 for respirometers includes: a plurality of detection heads S which are arranged near a movement range of the marker along a direction of movement of the marker and a calibration storage unit that stores calibration information for the detection heads and the respiratory scales by contrasting the position of one of the detection heads S to which the marker 6 has approached and the actual scale of the respirometer through a change in the output value of the one of the detection heads due to the approach by the marker 6. The respiration measuring conversion device 20 for respirometers also includes an output unit that outputs a value of the respiratory scale as an electrical signal.Linvention concerne : un dispositif de conversion de mesure de respiration pour respiromètres qui peut être facilement fixé à un respiromètre mécanique existant et qui numérise les valeurs mesurées un respiromètre muni du dispositif de conversion de mesure de respiration et un procédé de mesure de respiration. La présente invention concerne un dispositif de conversion de mesure de respiration pour respiromètres, le dispositif de conversion de mesure de respiration 20 convertissan
