Abstract: Roe W is loaded on a loading tray 6, the roe W is irradiated with light from light irradiation means 11, and an image of at least a part of the roe W irradiated with light from the light irradiation means 11 is taken by image pickup means 12. Image processing of the image Pa taken by the image pickup means 12 is performed to measure a light transmissive value of the light passing through the roe W; and maturity of the roe W is determined based on the measured light transmissive value. This enables a roe maturity determination device and a roe maturity determination method capable of determining precisely roe maturity.