A light emitting device for growing plants, the device emitting light having variable wavelengths by combining a plurality of wavelengths using quantum dots and comprising: a light emitting unit comprising at least one light source; a wavelength changing unit spaced apart from the light source by a predetermined distance and comprising a plurality of regions, each of the plurality of regions corresponding to each of, each column of, or each row of the at least one light source; a driving unit configured to change a region of the wavelength changing unit illuminated by the light source; and a control unit for controlling the driving unit to adjust a wavelength of output light, wherein the plurality of regions of the wavelength changing unit are separated either in rows or in columns, wherein, in order to change the region of the wavelength changing unit illuminated by the light source, the driving unit is configured to move the at least one light source or the wavelength changing unit either in a row direction or in a column direction, characterised in that each region of the wavelength changing unit has quantum dots corresponding to a predetermined wavelength, and the wavelength changing unit comprises a fifth region and at least one of a first region, a second region, a third region, a fourth region, and a sixth region, the first region having quantum dots for outputting red light, the second region having quantum dots for outputting green light, the third region having quantum dots for outputting blue light, the fourth region having at least two of the quantum dots for outputting red light, quantum dots for outputting green light, and quantum dots for outputting blue light, the fifth region having a layered structure of at least two of the first to fourth regions, and the sixth region allowing light emitted by the light emitting unit to output without changing a wavelength of the light. a light emitting unit comprising at least one light source; a wavelength changing unit spaced apart from the light source by a predetermined distance and comprising a plurality of regions, each of the plurality of regions corresponding to each of, each column of, or each row of the at least one light source; a driving unit configured to change a region of the wavelength changing unit illuminated by the light source; and a control unit for controlling the driving unit to adjust a wavelength of output light, wherein the plurality of regions of the wavelength changing unit are separated either in rows or in columns, wherein, in order to change the region of the wavelength changing unit illuminated by the light source, the driving unit is configured to move the at least one light source or the wavelength changing unit either in a row direction or in a column direction, characterised in that each region of the wavelength changing unit has quantum dots corresponding to a predetermined wavelength, and the wavelength changing unit comprises a fifth region and at least one of a first region, a second region, a third region, a fourth region, and a sixth region, the first region having quantum dots for outputting red light, the second region having quantum dots for outputting green light, the third region having quantum dots for outputting blue light, the fourth region having at least two of the quantum dots for outputting red light, quantum dots for outputting green light, and quantum dots for outputting blue light, the fifth region having a layered structure of at least two of the first to fourth regions, and the sixth region allowing light emitted by the light emitting unit to output without changing a wavelength of the light.