A condenser microphone is disclosed. The condenser microphone includes a substrate having a cavity, a backplate connected to the substrate, a diaphragm facing to the backplate, and an anchor supporting the diaphragm. A first gap is formed between the diaphragm and the backplate. A groove is arranged on the anchor and the diaphragm partially covers the groove. The diaphragm and the groove forms a second gap communicating with the first gap.