We investigate the rheological properties of an assembly of inelastic (but frictionless) particles close to the jamming density using numerical simulation, in which uniform steady states with a constant shear rate $dotgamma$ is realized. The system behaves as a power-law fluid and the relevant exponents are estimated; e.g., the shear stress is proportional to $dotgamma^{1/delta_S}$, where $1/delta_S=0.64(2)$. It is also found that the relaxation time $tau$ and the correlation length $xi$ of the velocity increase obeying power laws: $tausimdotgamma^{-beta}$ and $xisimdotgamma^{-alpha}$, where $beta=0.27(3)$ and $alpha=0.23(3)$.
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