[Problem] With regard to an electroacoustic conversion device, to facilitate miniaturization and, in particular, thinning, and the stabilizing of characteristics. [Solution] A drive magnet 37 and a pole piece 39 are fixed in a yoke 35. Fixed to the yoke 35 is a ring-shaped flange part 45 which is thinner than the yoke 35, and which protrudes in the outer circumferential direction at the end of the yoke 35. At the outer circumferential edge of the flange part 45, an annular attachment section 45b is disposed in an extending manner, and an annular contact section 45c is disposed in an extending manner on the outside of the attachment section 45b. A vibration film 47 is attached to the attachment section 45b so as to cover the pole piece 39 and the flange part 45. A voice coil 49 is fixed to the vibration film 47, and the voice coil is inserted between the pole piece 39 and the yoke 35. The inner wall of a case body 53 comes into contact with the contact section 45c.