The electrically conductive adhesive (Isotropic Conductive Adhesive: ICA) is a paste-like and high-viscosity liquid composed of organic binder and inorganic filler. In recent years, ICA has gradually replaced lead solder as a jointing material for electronics packaging due to its-advantageous properties such as low-temperature junction, stress relaxation, safety, and ease of recycling. On the other hand, further improvements are still required in terms of electrical conductivity, heat conductivity and adhesion strength. In this research, in order to discuss the effect of polymer resin on electrical conductivity, the relationship between cure temperature, volume change, curing reaction in during the curing process and the emergence of conductivity was investigated by using ICA composed of atomized spherical silver particles and five different resins. As a result, it was confirmed that there was no obvious relationship between volume shrinkage of resin and electric resistivity of the ICA during the curing process and that the conductivity of the ICA was based neither on volume shrinkage of resin nor on the shortening of the distance between the fillers during the curing process. It was also confirmed that curing reactions in the polymer matrix were not necessarily required for the emergence of conductivity. These results suggest that there may be other influential factors such as the interaction between metal fillers and polymer resins.