Disclosed herein are a penile tumescence diagnosis device and method. The penile tumescence diagnosis device includes: a plurality of ring sensors configured to measure a body part of a user and generate sensor-sensed information; and a processor configured to generate diagnostic information about the body part of the user based on the sensor-sensed information generated by the plurality of ring sensors. The plurality of ring sensors includes: a first ring sensor configured to have a first threshold length and be disposed on the body part to surround the body part in a ring shape; and a second ring sensor configured to have a second threshold length larger than the first threshold length and be disposed on the body part to surround the body part in a ring shape.