Transcranial static magnetic field stimulation (tSMS), which uses static magnetic fields produced by a small and strong neodymium magnet placed on the scalp, is a new member of non-invasive brain stimulation family. tSMS can reduce the cortical excitability in the cerebral cortex just below the magnet as well as modulate the function of the cerebral cortex contralateral to the stimulation side via the brain network. tSMS is a promising neuromodulatory technique for a safe, low-cost, and easy therapeutic tool. However, the neurophysiological mechanisms how local tSMS changes the whole brain network remains elusive. In this study, we investigated the neuromodulation induced by tSMS using transcranial magnetic stimulation (TMS) - electroencephalography (EEG), in which EEG signal is recorded during TMS. The co-registration of TMS and EEG can provide valuable information about the characteristics of cortical reactivity in response to magnetic stimuli.Fifteen healthy people participated in this study. TMS-EEG was recorded before and after tSMS applied over the left primary motor cortex (M1) for 20 min. We analyzed the TMS-evoked potentials (TEPs), which are the EEG responses time-locked to the TMS pulse. The amplitude of the peak around 30 ms after the TMS pulse significantly decreased after tSMS at the left primary sensorimotor area (SM1), while that around 60 ms after the TMS pulse significantly increased after tSMS at the right SM1.tSMS altered TEPs both at the stimulated cortex and at the contralateral cortex. The finding would be related to the neurophysiological mechanisms underlying the neuromodulation induced by tSMS.