Earphones including condenser type electroacoustic transducers exhibit compatibility between an open type earphone mode and a closed type earphone mode for improving convenience. An exemplary earphone includes a diaphragm, at least one fixed electrode constituting a capacitor with the diaphragm, a housing accommodating the diaphragm and the at least one fixed electrode, the housing having an interior and an exterior, a sound conduit protruding forward from the housing, communication holes establishing communication between the interior and the exterior of the housing, and an opening and closing mechanism to open and close the communication holes. The sum of the volume of the interior space of the sound conduit and the volume of the space in a front of the diaphragm in communication with the interior space of the sound conduit in the interior space of the housing is smaller than the volume of the space in a rear of the diaphragm in the interior space of the housing.