The present invention provides a target recognizing element wherein a
receptor is fixed to an inclusion complex containing a mediator. The
target recognizing element includes a first host molecule having
hydrophilic groups and an inclusion site, a second host molecule having
hydrophilic groups and an inclusion site, a receptor which is bonded to
the hydrophilic groups of the second host molecule and which reacts with
the target, and a guest molecule which is included by the inclusion site
of the first host molecule and the inclusion site of the second host
molecule and which transfers an electric charge generated by the reaction
between the target and the receptor.