A ribbon microphone unit includes a permanent magnet that forms a magnetic field and a ribbon diaphragm that is disposed in the magnetic field and vibrates upon receiving a sound wave. An elastic layer made of synthetic resin is formed at least at a portion of the ribbon diaphragm, the portion vibrating upon receiving the sound wave. Preferably, the ribbon diaphragm is formed into triangular waves with the portion vibrating upon receiving sound waves being alternately folded along lines in a width direction across the entire length. The elastic layer may be formed on one or both surfaces of the ribbon diaphragm and may be provided only at both side ends of the ribbon diaphragm.