As an apparatus for manufacturing a micro lens array includes a first substrate having a plurality of cavities formed at locations corresponding to locations of the plurality of micro lenses, and a second substrate having a lower softening point than the first substrate and bonded on the first substrate to close the plurality of cavities, wherein a portion of the second substrate located on the cavities swells convexly by air trapped in the cavities expanding its volume in response to a temperature above the softening point of the second substrate being applied, to form domes corresponding to a shape of the micro lenses, and the micro lens array is cast using the second substrate having the formed domes as a mold.