PURPOSE: A hydroponic apparatus is provided to have an effect capable of improving the energy efficiency by using the vertical fall using gravity by the driving force by a circulation pump. CONSTITUTION: A hydroponic apparatus has a circulation structure. The circulation structure collects culture medium which has ascended to a circulation pipe by a circulation pump (11) of a reservoir (10) into a culture medium circulation part, using a tray formed in a preset inclination. The culture medium circulation part comprises an upper end culture medium circulation part (30), a first central culture medium circulation part (50), a second culture medium circulation part (60) and a third central culture medium circulation part (70). The upper end culture medium circulation part and the first central culture medium circulation part has a first preset inclination. A first circulation pipe (20) is formed in a structure to be connected to a supply hole formed in a first tray of the upper end culture medium circulation par
