To provide an air bleed device of a conduit for efficiently conducting air bleed from the conduit such as a water pipe which is free from a trouble of cleaning work by the pressure-feed of a cleaning body.

The air bleed device is provided with a swell-out chamber 1 swelling to have a diameter larger than the conduit constituting pipe, a riser pipe 2 provided to communicate with an upper part of the swell-out chamber, a float valve mechanism 3 mounted to the riser pipe, connection parts 42a, 42b with the conduit structuring pipes A1, A2 arranged side by side, connection pipes 4a, 4b composed of connection pipes 41a, 41b having the same pipe diameters as the conduit constituting pipes and arranged at right and left of the swell-out part in a communicating manner and a guide 5 formed of a plurality of guide rods installed between the right and left connecting pipes without reducing its inner diameter.