To provide a plant water dynamics sensor usable for measuring the dynamics of water flowing in a fine point of a plant such as a distal end of a new branch or a pedicel. The plant water dynamics sensor comprises: a heater-equipped temperature probe 10 including a temperature sensor 11 and a heater 12 a temperature probe 20 including a temperature sensor 21 an electrical resistance probe 30 including an electrical resistance measurement electrode 33 and a support 80 that supports the probes 10, 20, and 30 while the probes are aligned parallel to each other. The position of a xylem XY can be detected based on an electrical resistance measured at the electrical resistance probe 30, so that each of the temperature sensors 11 and 21 can be arranged correctly in a position at a phloem PH or at the xylem XY. This facilitates attachment of a plant water dynamics sensor 1 and water dynamics in a plant can be measured with high accuracy.
