Transcranial magnetic stimulation (TMS) is a noninvasive technique that modulates brain activity via an electric field induced by a coil placed on the scalp. However, its biophysical mechanisms of action are not fully understood, despite its use in clinical treatments. To investigate the effects of TMS on neuronal networks in detail through computer simulations, we implemented a TMS model and integrated it with a biophysically detailed model of the mouse visual cortex column. Specifically, we examined how the coil in our TMS model generates electric fields and how these fields affect the activity of single neurons as well as their local network. Our results show that the spatial relationship between the scalp coil and the cortical columns significantly influences membrane potentials and neuronal activity. In particular, the orientation of the TMS plays an essential role in evoking strong activity within the column. These findings suggest that biophysical neuron models are valuable tools for understanding the mechanisms of TMS effects.