An electromagnetic induction type acoustic transducer including a plate as an assembly of a magnetic circuit and having an opening of a predetermined diameter about a central axis, a pole piece as an assembly of the magnetic circuit and protruded on the central axis, having an outer peripheral diameter smaller than the opening of the plate and having an upper surface located lower than a lower surface of an opening peripheral portion of the plate by a predetermined distance, a lower surface portion of the opening peripheral portion of the plate and an upper surface portion of the pole piece constitute a magnetic gap of the magnetic circuit,a diaphragm vibrated in the upper and lower direction on the central axis at the position perpendicular to the central axis in the predetermined distance, an annular ring attached to the diaphragm at the position of the magnetic gap, and a coil attached to the plate and/or pole piece.