We investigate the formation of molecular clouds from atomic gas by using three-dimensional magnetohydrodynamical simulations including chemical reactions and heating/cooling processes. We consider super-Alfv\'enic head-on colliding flows of atomic gas possessing the two-phase structure. We examine how the molecular cloud formation changes depending on the angle \(\theta\) between the upstream flow and mean magnetic field. If the atomic gas is compressed almost along the mean magnetic field, super-Alfv\'enic anisotropic turbulence is maintained by accretion of the highly inhomogeneous upstream atomic gas, and the post-shock layer rapidly expands. Even a small obliqueness of the magnetic field drastically changes the physical properties of the post-shock layers. The shock compression amplifies the tangential component of the magnetic field which weakens the post-shock turbulence, making the post-shock layer denser. If the magnetic field is further inclined to the upstream flow, the shock-amplified magnetic pressure suppresses gas compression, leading to an extended post-shock layer. Our results, therefore, show that there is a critical angle \(\theta_\mathrm{cr}\). Compression with \(\theta<\theta_\mathrm{cr}\) generates largely-extended turbulence-dominated cold clouds. Around \(\theta\sim \theta_\mathrm{cr}\), dense cold clouds form. For \(\theta\gg \theta_\mathrm{cr}\), the strong magnetic pressure suppresses the formation of cold clouds. Efficient MC formation is expected if \(\theta\) is less than a few times \(\theta_\mathrm{cr}\).