The third-order upwind finite difference scheme is applied to the convective terms in three-dimensional Navier-Stokes equations to simulate directly the free jet flow emitted from a slit nozzle. The calculated flow field ranges from the nozzle exit to the fully developed turbulent region. The calculated results of turbulent characteristics (turbulent intensity distributions, Reynolds stresses, power spectra, and velocity autocorrelations) are compared with the experimental data. The mesh size is roughly ten times the kolmogorov microscale; however, the calculated turbulent characteristics fairly well represent the experimental ones, except that the data strongly depend upon small-scale eddies. This means that the simulation well documents the motion of large scale eddies which play an important role in a flow-field formation. The neglect of the small-scale eddies in the third-order upwind finite difference scheme does not greatly affect the calculated results of large-scale eddy motions.