This study aimed to compare electroencephalographic (EEG) activity between high- and low-motor learning groups (n = 10 each) during observation of, preparation for, and execution of a motor learning task. The subjects performed a ball rotation task in which two balls were rotated clockwise with the right hand. Each trial started with a rest period (5 s), subjects then observed the task action on a computer screen (30 s), this was followed by another rest (5 s), preparation for performing the action (5 s), and finally action execution (30 s); five trials were performed. The number of rotations during execution and EEG activities during observation, preparation, and execution were recorded. The EEG data of the high-motor learning group were compared with those of the low-motor learning group and were analyzed using exact low-resolution electromagnetic tomography (eLORETA). The left sensorimotor and parietal areas of the high-motor learning group showed a greater decrease in the alpha-2 (10.5-12.0 Hz) and beta-2 (18.5-21.0 Hz) rhythms than those of the low-motor learning group during all three phases of the trials. The study results suggest that the decreases in the alpha-2 and beta-2 rhythms in these areas during observation, preparation, and execution are associated with motor skill improvement.