To accurately acquire body composition information using data acquired by another device. Thus, there is provided a body composition monitor with scale including a communication unit for allowing input of biological component information (cross-sectional area, site length, subcutaneous fat percentage, visceral fat percentage, etc.) of a living body measured with another device such as an MRI, where step of calculating the body composition of the living body based on the biological component information, an impedance detected by an impedance detection unit, and a weight measured by a load detection unit is executed.