The invention allows a user to exercise effectively. A desired exercise effect is not obtained when the user puts too much weight onto a seat. To prevent this, an exercise assist device comprises a limit switch that detects whether a predetermined load (weight) is applied to foot rests, i.e., whether the user steps on the foot rests properly and exercises successfully. A control circuit controls a drive device for swinging the seat; obtains the number of successes relative to the total number of swings, and a success rate, based on detection results by the limit switch; displays the number of successes and the success rate on a display panel, and controls the rotational speed of a motor via a motor control circuit. As a result, the device determines automatically the degree of exercise proficiency of the user, and allows the user to exercise effectively in accordance with his/her degree of the proficiency.