  We study the current algebras of the NS5-branes, the Kaluza-Klein (KK)
five-branes and the exotic $5^2_2$-branes in type IIA/IIB superstring theories.
Their worldvolume theories are governed by the six-dimensional $\mathcal{N}=
(2,0)$ tensor and the $\mathcal{N} = (1,1)$ vector multiplets. We show that the
current algebras are determined through the S- and T-dualities. The algebras of
the $\mathcal{N} = (2,0)$ theories are characterized by the Dirac bracket
caused by the self-dual gauge field in the five-brane worldvolumes, while those
of the $\mathcal{N} = (1,1)$ theories are given by the Poisson bracket. By the
use of these algebras, we examine extended spaces in terms of tensor
coordinates which are the representation of ten-dimensional supersymmetry. We
also examine the transition rules of the currents in the type IIA/IIB
supersymmetry algebras in ten dimensions. Based on the algebras, we write down
the section conditions in the extended spaces and gauge transformations of the
supergravity fields.
