A novel heat exchanger using parallel small refrigerant channels has recently been developed for air conditioning systems. To do this, it is necessary to clarify the characteristics of boiling heat transfer in non-uniformly heated parallel mini-channels. In this study, experiments on flow boiling in non-uniformly heated two parallel mini-channels were carried out and the characteristics of flow distribution and flow boiling heat transfer were investigated. When the difference of heat flux between the two channels was large, the maldistribution of different flow rates and inlet qualities of the channels occurred. In the higher heated channel, flow rate was lower than the average flow rate of the two channels and heat transfer coefficient decreased especially near the outlet.