auxiliary air flow passage can be increased to about three times that of the radius of the main air flow passage in the ninth embodiment shown in fig1 a spider 31 is disposed across the main air flow passage like the spider 3g shown in fig1 the spider has in it an axial auxiliary air flow passage portion 47 whose inlet opening is located at a position offset from the axis of the main air flow passage 2 and a single composite radial auxiliary air flow passage portion 47e consisting of a single radial air flow passage portion 47a connected to the axial auxiliary air flow passage portion 47 and two air flow passage portions 47b and 47c branching from the air flow passage portion 47a as in the case of the embodiment shown in fig9 the air flow passage portions 47b and 47c respectively have openings 47f and 47g at the central portion of the main air flow passage the portions of the air flow passage portions 47b and 47c which branch from the air flow passage portion 47a are curved to form portions 47h and 47i for changing the direction of air flow by about 180 u00b0 in each of the embodiments shown in fig1 to 13 the length of the auxiliary air flow passage is increased as in the preceding embodiments consequently the two value phenomena caused by pulsations in the intake air flow which occur downstream of the air flow meter can be prevented very effectively in the embodiments shown in fig1 to 13 the inlet opening of each of the axial.