An electroacoustic transducer includes an electromechanical transducer and a casing. The electromechanical transducer transduces an electric signal into mechanical vibration. The housing can be attached to a cavum conchae without blocking an external auditory canal, in which the electromechanical transducer is housed, and vibrates due to the mechanical vibration caused by the electromechanical transducer to generate sound. The housing includes an inner housing portion located on the external auditory canal side and an outer housing portion located on an external environment side when the housing is attached to the cavum conchae. The housing has an ellipsoidal shape or an oval shape.