An evaporator utilizes micro-channel tubes, and more particularly, has a structure of a heat exchanger using micro-channel tubes, which is applied to an evaporator of a household air conditioner. The evaporator, using micro-channel tubes, includes a first heat exchanging unit including a pair of upper and lower headers, and a plurality of the micro-channel tubes erected vertically between the headers so that condensed water flows downward, and a second heat exchanging unit, installed adjacent to the first heat exchanging unit, includes a pair of upper and lower headers, and a plurality of the micro-channel tubes erected vertically between the headers so that condensed water flows downward. A plurality of return pipes connect upper headers of neighboring heat exchanging units to transmit refrigerant between the neighboring heat exchanging units.