Superstring theory includes a lot of massive higher spin
excitations, and there would appear a higher spin
gauge symmetry at the tensionless limit. Moreover, it
has been expected that these states could be described
by a broken phase of higher spin gauge theory.
Recently, it becomes possible to discuss the
realizations of the idea with the help of Vasiliev theory
and AdS/CFT correspondence. In this talk, I will explain
recent developments on the concrete relation between
higher spin gauge theory and superstring theory by
making use of AdS/CFT correspondence. In particular, I
will focus on the AdS_3 case. Moreover, I will show that
higher spin fields become massive due to the braking of
higher spin symmetry using a simple example.