  We study the large N reduced model of D-dimensional Yang-Mills theory with
special attention to the dynamical aspects related to the eigenvalues of the
NxN matrices, which correspond to the space-time coordinates in the IIB matrix
model. We define a quantity which represents the uncertainty of the space-time
coordinates and show that it is of the same order as the extent of the space
time, which means that the classical space-time picture is maximally broken.
The absence of the SSB of the Lorentz invariance is also shown.
