This study compared activation of the sensorimotor area using magnetoencephalography after unilateral and bilateral movements. Thirteen healthy individuals and a patient with mild hemiplegia performed unilateral and bilateral forearm pronation movements. Among healthy participants, there were no significant differences in motor-evoked field during unilateral and bilateral movements, and equivalent current dipoles were located around the sensorimotor area. In the patient, motor-evoked field was measured in the lesional hemisphere clearly during bilateral movements, and the locus of equivalent current dipoles was estimated to be around the mean location in healthy individuals. In contrast, unilateral movements were estimated outside the area of sensorimotor activation. We speculate that bilateral movements may be more effective for functional recovery during rehabilitation.