Flux cored wire (FCW) is a type of welding consumable used as an electrode in gas metal arc welding (GMAW). The wire consists of a metal sheath filled with flux. Compared with solid wire, molten metal droplets are transported to the weld pool along the flux column. Empirically, this droplet transfer mode is known to generate fewer spatters during GMAW with FCW [1]. However, the mechanism underlying the formation of the flux column has not yet been clarified. In this study, molten metal droplet transfer phenomena were simulated using a computational model based on the three-dimensional Smoothed Particle Hydrodynamics (SPH) method in order to elucidate the mechanism of flux column formation during GMAW with FCW. Furthermore, simulations with different values of specific heat and thermal conductivity were performed to investigate the influence of heat conduction in the wire on flux column formation. The results demonstrated that a flux column formed at the wire tip, and molten metal droplets traveled downstream along this column to the weld pool, which was observed in actural this welding process. In addition, when the flux component had a lower specific heat and higher thermal conductivity than TiO₂, the flux column did not form. These findings indicated that heat conduction within the flux played an important role in flux column formation during GMAW with FCW.