An earphone comprising: an electroacoustic transducer for converting an audio signal into sound, and a housing for holding the electroacoustic transducer, the housing including a sound output unit for introducing the sound produced by the electroacoustic transducer into the external auditory meatus of an ear when the housing is placed in the ear, wherein said housing comprises a front housing that surrounds a front of the electroacoustic transducer and a rear housing that is combined with the front housing and surrounds a rear of the electroacoustic transducer, the rear housing comprises a rear wall that surrounds the rear of the electroacoustic transducer and a base wall that extends from the rear wall to the front of the electroacoustic transducer and forms the sound output unit together with the front housing, said housing further comprising a first space located in the rear of the electroacoustic transducer and a second space located in the front of the electroacoustic transducer, the second space is larger than the first space and is operatively connected to the sound output unit, a rear opening in the rear housing operatively connects the first space to the outside and a front opening in the front housing is adjacent to the front of the electoacoustic transducer and operatively connects the second space to the outside, said electroacoustic transducer emits sound in a sound emission direction which is transverse to the external auditory meatus of the ear and which is substantially parallel to a side of a cavum concha of the ear, and said base wall is adapted to contact the side of the cavum concha of the ear an electroacoustic transducer for converting an audio signal into sound, and a housing for holding the electroacoustic transducer, the housing including a sound output unit for introducing the sound produced by the electroacoustic transducer into the external auditory meatus of an ear when the housing is placed in the ear, wherein said housing comprises a front housing that surrounds a front of the electroacoustic transducer and a rear housing that is combined with the front housing and surrounds a rear of the electroacoustic transducer, the rear housing comprises a rear wall that surrounds the rear of the electroacoustic transducer and a base wall that extends from the rear wall to the front of the electroacoustic transducer and forms the sound output unit together with the front housing, said housing further comprising a first space located in the rear of the electroacoustic transducer and a second space located in the front of the electroacoustic transducer, the second space is larger than the first space and is operatively connected to the sound output unit, a rear opening in the rear housing operatively connects the first space to the outside and a front opening in the front housing is adjacent to the front of the electoacoustic transducer and operatively connects the second space to the outside, said electroacoustic transducer emits sound in a sound emission direction which is transverse to the external auditory meatus of the ear and which is substantially parallel to a side of a cavum concha of the ear, and said base wall is adapted to contact the side of the cavum concha of the ear