We performed an intermittent growth of InAs quantum dots (QD) on GaAs(001) at 500 °C. The transition of surface structures during the growth was investigated by using reflection high energy electron diffraction observation. We also performed in situ observation of QD nucleation by using STMBE system in which a scanning tunneling microscope equipped within a molecular beam epitaxy chamber. We have found that the initial QDs formation occurred from 1.15 to 1.38 ML with the intermittent InAs supply. This InAs supply amount was much smaller than that of ordinary continuous deposition (∼1.66 ML). Moreover, the QDs mainly appeared on the terrace while they mainly appear on step edges by continuous growth at 500 °C. This indicates that the annealing parts of the intermittent growth affected the surface atomic structures of InGaAs wetting layer, uniforming the In fluctuation and stabilized the surface morphology. By the preparation of large (n×3) and (2×4) area, the QD nucleation occurs with a smaller InAs supply on the surface.