Abstract: A gas measuring apparatus (100), including: a gas collecting device (102), including two gas entrapping compartments (1021, 1022); a fixing frame (103), which is rotatably connected with the gas collecting device (102); positioning holders (104, 105), each of which is located below a corresponding one of the two gas entrapping compartments (1021, 1022) and is configured to limit the rotation angle of the gas collecting device (102) by colliding with an edge of the corresponding one of the gas entrapping compartments (1021, 1022); a chamber (101), which accommodates the gas collecting device (102), the fixing frame (103), the positioning holders (104, 105) and a liquid medium; and a gas inlet (106), which is located below the gas collecting device (102). The apparatus (100) solves the problem of relatively low accuracy of measurement results.