A multi-wavelength optical transmitting module includes a housing, an optical output block, an optical transmitting block, and an optical multiplexer (MUX) block. The housing has a first coupling hole and a second coupling hole respectively formed in opposite surfaces thereof. The optical output block is coupled to the first coupling hole of the housing, is connected to an optical signal connector, and includes a first lens. The optical transmitting block is coupled to the second coupling hole of the housing and is connected to an electrical signal connector. In addition, the optical transmitting block includes a plurality of transmitting devices which respectively output light having different wavelengths and are arranged parallel to the optical output block, and a plurality of second lenses which are arranged on a light output side of the transmitting devices to correspond respectively to the transmitting devices. The optical multiplexer (MUX) block is disposed within the housing, multiplexes optical signals of multiple wavelengths, which were output from the transmitting devices and passed through the second is lenses, and transmits the multiplexed optical signals to the optical output block.