PROBLEM TO BE SOLVED: To provide a heating value imparting device and the like for calculating a flow rate of a liquid flowing inside a surface portion of a plant such as bark, which do not require to determine a sheath conductance Kr, do not ignore a heat quantity Qstored in a portion covered with an inside heater, and can prevent the surface portion of the plant from being heated to a high temperature.SOLUTION: A heating value imparting device includes: an inside heater 11c which heats a surface portion of a plant over the entire circumference; a cork sheet 12 arranged in the outer peripheral side of the inside heater 11c; and an outer heater 11o arranged in the outer peripheral side of the cork sheet 12. The inside heater 11c heats the entire circumference of the surface portion of the plant to a predetermined target temperature and keeps the temperature of the entire circumference of the surface portion of the plant at the target temperature, and the outer heater 11o heats a portion to be heated by the ou
