We study a system composed of a mixture of different-sized spherical quantum dots (QDs) involving optical near-field (ONF) interactions to induce effective optical excitation transfer. Here energy transfer was explained by resonant energy transfer via the optical near-field interaction between the first excited state of small QDs and the second excited state of large QDs. The energy transfer in a film of different-sized QDs made of CdTe and CdSe were experimentally demonstrated. An analysis between the optical near field transfer rate [1] and F¨orster type transfer rate was made. The proper understanding of the exciton transfer between these QDs is important for the design and implementation of near-field photonic devices employing them. [1] M. Ohtsu, et al., Principles of Nanophotonics, CRC Press (2008).