  We investigate entanglement entropy in a scalar field theory on the fuzzy
sphere. The theory is realized by a matrix model. In our previous study, we
confirmed that entanglement entropy in the free case is proportional to the
square of the boundary area of a focused region. Here we argue that this
behavior of entanglement entropy can be understood by the fact that the theory
is regularized by matrices, and further examine the dependence of entanglement
entropy on the matrix size. In the interacting case, by performing Monte Carlo
simulations, we observe a transition from a generalized volume law, which is
obtained by integrating the square of area law, to the square of area law.
