The present invention provides a hydroponic device and a hydroponic method with which it is possible to remove waste and unwanted bacteria in a cultivation tank. The hydroponic device according to the present invention is provided with a cultivation tank and a discharge mechanism that discharges liquid retained in the cultivation tank; and the discharge mechanism is provided with a pipe-like first drainage part provided at the bottom of the cultivation tank so as to pass therethrough in the top-to-bottom direction, a second drainage part that is connected to the top end of the first drainage part and the diameter of which increases upward from this top end like a funnel, liquid inlet holes that are formed in a circumferential wall of the second drainage part and that allow liquid retained in the cultivation tank to flow inside the second drainage part, protrusions that are provided below the liquid inlet holes and that protrude from the inner surface of the circumferential wall of the second drainage part along the circumferential direction of the second drainage part, so as to generate a swirling flow in the liquid that has flowed inside the second drainage part via the liquid inlet holes, and a lid that is formed in a bowl shape and with which it is possible to make the liquid retained in the cultivation tank flow inside the second drainage part via the liquid inlet holes in a state in which the first drainage part and the second drainage part are covered from above with the lid.