A voice input unit has predetermined directivity for acquiring a voice. A sound source arrival direction estimation unit operating as a first direction detection unit detects a first direction, which is an arrival direction of a signal voice of a predetermined target, from the acquired voice. Moreover, a sound source arrival direction estimation unit operating as a second direction detection unit detects a second direction, which is an arrival direction of a noise voice, from the acquired voice. A sound source separation unit, a sound volume calculation unit, and a detection unit having an S/N ratio calculation unit detect a sound source separation direction or a sound source separation position, based on the first direction and the second direction.