Abstract: A method and apparatus for screening a microorganism or protein having a useful function by using a micro-chamber array. Using the screening method and screening apparatus in accordance with the present invention, a target protein having an enzymatic activity or a microorganism producing such a protein is screened from a sample serving as a screening object by using a base plate having a plurality of micro-chambers arranged in the form of an array. With this method and apparatus, a protein having an enzymatic activity or a microorganism producing such a protein that is present in a micro-chamber is detected by detecting a fluorescence produced by an enzyme reaction of the protein having an enzymatic activity and a fluorescence substrate.