The development of microstructure-regulated three dimensional（3-D）materials has attracted much attention for scaffold in the field of tissue engineering, carrier of drug delivery systems, and soft actuators. For example, living tissues are 3-D matrices with highly organized and stratified architectures. Adhesion of soft materials including hydrogels has therefore attracted attention because it is one of the most important processes for building functional soft constructs. To develop functional and microstructure-regulated devices using hydrogels, the “adhesion” of hydrogels is required. We recently reported a novel strategy for the adhesion of cationic and anionic hydrogels. The adhesion of the hydrogels was achieved via electrophoresis to deliver the polyions inside the gels, and to form a polyion complex at the interface between the two hydrogels for adhesion. The present novel adhesion strategy will be useful not only for the adhesion of gels, but also for the fabrication of novel gel constructs.