The effects of geometric properties such as diameter, d, number, n and pitch, p, for holes located on a perforated plate on gas holdup, phi, in a bubble column were experimentally investigated while varying gas flow rate, G, and unaerated liquid height, Z(0). In the case of constant Z(0), the volume of the spouting section above the column bottom increased with increasing d and decreasing n and p, and became negligible compared with that of the calming section at sufficiently large Z(0). As a result, the value of phi based on the volume of the bubble bed increased and approached that of phi(C) based on the volume of the calming section. The value of phi(C) was correlated to two parameters as a dimensionless expression. One was the flow parameter defined by a ratio of the reference velocities in the free and recirculated rising regions, and another was the distribution parameter for gas holdup in the recirculated rising region. Since the latter was strongly dependent on geometric properties for a perforated plate, its empirical expression was obtained as a function of the properties.