The stabilization characteristics of the vibratory sand compaction pile method, popularly being adopted in Japan for stabilization of soft soil, as applied to cohesionless subsoils, have been examined in the aspect of its practical applications. Referring to numerous examples of standard penetration tests carried out before and after treatment to check the stabilization effect in the field, the influences of five factors related to cohesionless subsoil compaction, depth from ground level, sand/gravel content, N-value of original ground, sand pile area ratio and vibrator size, on the N-value of treated ground have been investigated.