  We studied roles of a turbulent resistivity in the core-collapse of a
strongly magnetized massive star, carrying out 2D-resistive-MHD simulations.
The three cases with different initial strengths of magnetic field and rotation
are investigated; 1. strongly magnetized rotating core; 2.moderately magnetized
rotating core; 3. very strongly magnetized non-rotating core. In each case,
both an ideal-MHD model and resistive-MHD models are computed. As a result of
computations, each model shows a matter eruption helped by a magnetic
acceleration (and also by a centrifugal acceleration in the rotating cases). We
found that a resistivity attenuates the explosion in case~1 and 2, while it
enhances the explosion in case~3. We also found that in the rotating cases,
main mechanisms for the amplification of a magnetic field in the post-bounce
phase are an outward advection of magnetic field and a winding of poloidal
magnetic field-lines by differential rotation, which are somewhat dampened down
with the presence of a resistivity. Although the magnetorotational instability
seems to occur in the rotating models, it will play only a minor role in a
magnetic field amplification. Another impact of resistivity is that on the
aspect ratio. In the rotating cases, a large aspect ratio of the ejected
matters, $> 2.5$, attained in a ideal-MHD model is reduced to some extent in a
resistive model. These results indicate that a resistivity possibly plays an
important role in the dynamics of strongly magnetized supernovae.
