In this study, we present the spontaneous adhesion of two thermoreversible physically cross-linked hydrogels via molecular recognition under a physiological condition. We successfully prepared two types of hydrogels generated using two kinds of well-defined ABA type triblock copolymers: CAT-ABA and PBA-ABA, which contain catechol and phenylboronic acid groups as functional side chains, respectively. Both types of ABA triblock copolymers were able to undergo sol-to-gel transition with the increase in temperature resulting from the formation of physical cross-links at a physiological temperature, which enables easy cell encapsulation in the hydrogel. It was determined that the cell encapsulating hydrogels exhibited spontaneous macroscopic adhesion through the formation of boronic esters between phenylboronic acid and catechol at the hydrogel interface. This novel system likely represents a promising method to construct a precisely organized, three-dimensional coculture system to enable the reconstruction of complicated tissues such as the liver in vitro.