This paper presents the results of an experimental study of wave-induced pore pressures in marine sediments. A one-dimensional facility was set up with a vertical cylinder, and a 1.8 m thick sandy deposit with 0.2 m of water above the deposit. Unlike the previous experiments of Zen and Yamazaki (1990a), additional static water pressures were added onto the harmonic dynamic wave pressure, which allowed us to simulate a case with a greater depth of water. Furthermore, more pore pressure gauges were installed to better resolve the distribution of the pore pressure. A series of experiments with 3000 wave cycles in each test were conducted under various wave and soil conditions. This allowed examining the influence of the wave and soil parameters on the wave-induced pore pressures as well as liquefaction. The experimental results show the significant influence of liquefaction on sandy deposits in shallow water. Furthermore, the thickness of the sandy deposit was usually considered to be unchanged in theoretical calculations, while the thickness was observed to change periodically with the loadings.