Abstract: [Object] To suppress the variations in the growth of cultivation products to perform stable production, and reduce the power cost for applying artificial light. [Solving Means] A hydroponic cultivation system includes a hydroponic cultivation unit, a daylighting apparatus, an artificial light application apparatus, a daylighting sensor, and a control apparatus. The hydroponic cultivation unit includes a seedbed, a seedling of a plant to be cultivated being transplanted to the seedbed. The daylighting apparatus takes natural light through a daylighting port into a light emitting surface facing the seedbed, and emits the light from the light emitting surface toward the seedling. The artificial light application apparatus applies artificial light to the seedling. The daylighting sensor is provided at a position apart from the seedbed, and detects a light amount of the natural light emitted from the light emitting surface.