1. A motion analyzer comprising: a motion detection unit that detects motion of a part of a body of a subject; a first voice acquisition unit that is provided in a place where a distance of a sound wave propagation path from a mouth of the subject is a first distance; and a second voice acquisition unit that is provided in a place where a distance of a sound wave propagation path from the mouth of the subject is smaller than the first distance, a speaking detection unit that detects speaking of the subject on the basis of a sound pressure ratio is a ratio between sound pressure of a voice acquired by the first voice acquisition unit and sound pressure of a voice acquired by the second voice acquisition unit; and a determination unit that determines that the subject has performed predetermined motion when motion of a part of the body is detected by the motion detection unit and speaking of the subject is detected by the speaking detection unit.