The present invention provides an optical type body composition measuring device which can correctly measure body composition in a large area of an organism. A measuring part (30) is provided with the following components: an irradiation part which irradiates to skin, a first light receiving part (35) and a second light receiving part which receive the light that propagates in the organism. Additionally, for causing the measuring part (30) to smoothly slide in a random direction along the skin surface, a movable part (20) with a sphere (21) is mounted.
