Abstract Purpose The aim of present magnetoencephalography study was conducted to investigate how the cerebellum is involved in intracerebral activity immediately before conscious and voluntary teeth-clenching. Methods We recorded the neuromagnetic signal immediately before teeth-clenching in five healthy subjects. A single trial consisted of self-paced teeth-clenching for 2 s followed by a semi-randomized interval of 2–4 s, and 25 trials were performed in a single session. Each subject performed a total of 125 trials over 5 sessions. The subjects also performed five control sessions without the teeth-clenching task. The subjects were asked to observe a visual cue providing task information. We used magnetic field tomography to obtain a tomographic reconstruction of brain activity for each time slice of the average signal for each subject and session. Activation of regions of interest by cerebellar neuron activity was computed from the magnetic field tomography result. Results Cerebellar activation before the teeth-clenching task was identified in all five subjects: bilaterally in three, and unilaterally in two. The peak amplitudes for the left and right cerebellar hemispheres in the main session were significantly greater than those in the control session ( P < 0.01). Left and right cerebellar hemisphere activities were detected approximately 150 ms after visual cue. Conclusion Our findings suggest that the cerebellum is involved in the signal pathway immediately before teeth-clenching.