  We study the IIB matrix model in an interpretation where the matrices are
differential operators defined on curved spacetimes. In this interpretation,
coefficients of higher derivative operators formally appear to be massless
higher spin fields. In this paper, we examine whether the unitary symmetry of
the matrices includes appropriate higher spin gauge symmetries. We focus on
fields that are bosonic and relatively simple in the viewpoint of the
representation of Lorentz group. We find that the additional auxiliary fields
need to be introduced in order to see the higher spin gauge symmetries
explicitly. At the same time, we point out that a part of these extra fields
are gauged-away, and the rest of part can be written in terms of a totally
symmetric tensor field. The transformation to remove its longitudinal
components exists as well. As a result, we observe that the independent
physical DoF are the transverse components of that symmetric field, and that
the theory describes the corresponding higher spin field. We also find that the
field is not the Fronsdal field, rather the generalization of curvature.
