In this Letter, we report the growth of carbon nanofibers arrays by chemical vapor deposition in the presence of magnetic force. We find that when a magnet is applied carbon nanofibers arrays are grown and when the magnet is absent carbon nanotubes arrays are grown at the same experimental conditions. The nanofibers are worse in alignment and less in graphitization than those of the nanotubes grown at the same conditions. What is interesting is that two or three nanofibers can be connected together through a catalyst nanoparticle. These connections might be useful, especially in the fabrication of nanoelectronic devices.