To provide a plant sensor device capable of obtaining a parameter to determine a growth status other than a spectroscopy vegetation index without increasing its configuration. The plant sensor device includes a light emission part for emitting a measurement light to irradiate a target plant, a light receiving part for receiving a reflected light from the target plant, and a control section for controlling the light emission part and light receiving part. The control section determines a spectroscopy vegetation index of the target plant by obtaining a reflection rate of the target plant based on the measurement light and reflected light. The control section calculates a distance from the target plant to the light emission part in accordance with the measurement light and reflected light, and determines a plant height of the target plant based on the distance.
