The utility model discloses a microbial detection device, the power distribution box comprises a box body, the stand is installed on the top of fixing base down, the tray is installed on the top of branch, the culture dish has been placed to the upper surface of tray, the pneumatic valve is installed in the top left side of box, conical seat is installed to the inside bottom of pneumatic valve, the bottom of slide bar is installed the toper and is blocked up, the outer wall top of pneumatic valve is equipped with the gas pocket. This microbial detection device, through the stifled cooperationof culture dish, conical seat and toper, the culture dish is used for cultivation of microbes, and compression spring's elastic reaction makes that the toper is stifled to move down, plugs up conicalseat, makes the inside that the air can not getting into the, the anaerobic microorganisms's of being convenient for cultivation, if cultivateed the oxygen microorganism, the slide bar drives the stifled conical seat that upwards breaks away from of toper, inside that the air can getting into the, and the box can control and open or cut out and ventilate, and cultivation anaerobic microorganisms becomes reconciled the oxygen microorganism and can go on respectively, can satisfy user's user demand.