Electrical transport properties of extremely thin phosphosilicate glass (PSG) films containing Si nanocrystals (nc-Si) a few nanometers in diameter were studied. Samples were prepared by cosputtering Si and PSG targets, and post-annealing. Periodic Coulomb staircases were clearly observed in the DC current-voltage (I-V) characteristics along the vertical direction of films. Although the step structure was broadened with increasing temperature, it remained up to 200 K. The I-V curve could be well fitted by Monte Carlo simulation with a simple double-barrier structure model. Advantages of using PSG instead of SiO 2 as surrounding matrices of nc-Si to observe single-electron tunneling effects are discussed.