Electron holography, which is based on the interference of electron wave, is a powerful technique to visualize electromagnetic fields. We are devoted to precise measurements of the electromagnetic fields in many advanced materials, both in hard and soft matters. Special efforts are made to develop unique tools that are combined with electron holography: e.g., a magnetic-shielded pole piece dedicated to magnetic domain observations, and a special equipment to move microprobes inside the transmission electron microscope. These techniques enable simultaneous measurements of the electromagnetic fields, conductivity, structure, as well as composition at nanometer scale.