Dynamical contraction of a slowly-rotating magnetized cloud is studied using 2D magnetohydrodynamical (MHD) simulations. In the isothermal stage (n ≲ nA ∼ 1010cm−3), the cloud evolves similarly to that expected from the Larson-Penston self-similar solution and experiences a run-away collapse. However, after the central density exceeds ∼ nA, an accretion disk is formed around an adiabatic core. Just outside the core, an outflow is ejected by the effect of magnetic torque (magneto-centrifugal wind). Since ∼ 10% of the mass is ejected with almost all the angular momentum, the specific angular momentum of the protostellar core reduces to that observed in pre-main-sequence stars.