The purpose of this research is to elucidate the mechanism of lift generation and control in flapping flight of a mosquito. In this study, a tenfold enlarged realistic model of the flapping wing was used to simulate the motion of the mosquito's wing and flow pattern around it. Experiments were conducted using a very low speed wind tunnel to coincide the condition of Reynolds and Strouhal numbers with those of real mosquito. The flow field around the wing model was visualized using smoke and a laser light sheet, and was analyzed by a stereo-PIV system. In these experiments, we investigated the relationship between the flow field and the flapping angle. We found an unsteady ring vortex and a jet around the model wing. It was also found that the time-average of the lift was proportional to the square of flapping angle.