The collapse phenomena like an avalanche of sinter bed during charging of raw materials in the iron ore sintering are often observed. The collapse phenomena strongly influence the size segregation of raw materials in sinter bed, permeability and productivity of sinter. The reasons why collapse phenomena of the sinter bed during charging occur in the iron ore sintering have been discussed using the simulation by DEM (Discrete Element Method) in this work. As factors causing the collapse phenomena, there could be the granule shape of raw materials charged and the adhesion between the granules. First of all, a simulation model which is considered the adhesion force between the granules has been developed. The charging behavior of raw materials on the sintering machine was simulated by DEM. Effects of the adhesion force on deposition and collapse phenomena of the sinter bed were investigated. The deposition angle of the sinter bed obviously increases and the collapse phenomena of granules are clearly observed when the adhesion force was introduced into the granules. The ridges on the surface of the sinter bed which are feature of the collapse phenomena are confirmed. Therefore one of the reasons why the collapse phenomena occur during charging of the raw materials into the sintering machine would be adhesion of granules.