Disclosed are a plant growth lighting apparatus capable of forming a lighting region having a high degree of illuminance uniformity in the array direction of a light-emitting element array as well as a plant hydroponic cultivation apparatus and a plant hydroponic cultivation method capable of growing a plant with high growth efficiency even in a large cultivation region. A plurality of light-emitting element units, each including a first light-emitting element and a second light-emitting element having an emission peak wavelength different from that of the first light-emitting element, are arranged side by side along one direction to form a light-emitting element array. The light-emitting element unit is constituted by two second light-emitting elements disposed so as to be spaced apart from each other in the one direction and one first light-emitting element disposed between the two second light-emitting elements. A distance between first light-emitting elements in light-emitting element units adjacent to each other and positioned in an end part of the light-emitting element array is shorter than a distance between first light-emitting elements in light-emitting element units adjacent to each other and positioned in a central part of the light-emitting element array. A distance between two second light-emitting elements in a light-emitting element unit positioned in the end part is shorter than a distance between two second light-emitting elements in a light-emitting element unit positioned in the central part.
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