An auto feed humidification chamber with improved structure, the humidification chamber comprises a shell body, an extending tube, a float, a sealing element and a heated plate; the inside of the shell body is provided with a plurality of passage spacer plates, the extending tube is integrally formed on the inside of the shell body, the extending tube has a plurality of positioning blocks; the float is a hollow container, the central portion of the float has an extending portion, a top end of the extending portion has a plurality of hooks, the sealing element can be disposed on the top end of the extending portion; the heated plate is located below the shell body, and the heated plate is used for sealing the shell body to form a chamber space; wherein the extending portion can be suspended on the extending tube by the plurality hooks and the plurality positioning blocks, the passage spacer plates and the concave portions form at least two complicated gas passages in the chamber space, the outside surface of the float and the wall surface of the shell body form at least two annular gas passages in the chamber space.