PROBLEM TO BE SOLVED: To provide an apparatus for cultivating a plant, enabling the water content of soil to be accurately detected over a long period. SOLUTION: This apparatus for cultivating the plant 1 has a water content sensor 4 for detecting the water content of the soil 2. The water content sensor 4 is constituted of an optical water content sensor 4 the sensor part of which can detect the water content without contacting with the soil 2. The optical water content sensor 4 is constituted of a tungsten lamp 9 radiating light to the soil 2, a silicon photodiode 10 for detecting the light radiated from the tungsten lamp 9 and reflected by the soil 2, a pyroelectric element 11 and a sensor case 12 covering the tungsten lamp 9, the silicon photodiode 10 and the pyroelectric element 11. COPYRIGHT: (C)2005,JPO&NCIPI
