We review our recent numerical simulations of star formation. First, we show a simulation of magnetic turbulence in a plate-shaped self-gravitating stratified cloud. We find that the cloud is lifted up by the pressure of magnetic turbulence and reaches a steady-state characterized by oscillations about a new time-averaged equilibrium state. Next, we present a numerical simulation of gravitational fragmentation of the plate-shaped magnetized cloud. For strong magnetic field cases, we confirm that the gravitational instability develops gradually on a time scale characteristic of ambipolar diffusion. Finally, a numerical simulation of jet formation is shown. The important factors of jet formation are the magnetic field and rotation of a disk around a star.