Wide-body mouse and mouse widening device

A first side face and a second side face of the wide-body mouse make contact with the inner side faces of a thumb and a little finger of a relaxing hand, a left key is located below an index finger (used by the right hand) or a ring finger (used by the left hand) of the relaxing hand, and a middle key and an idler wheel are located below the middle finger. The right key is located below the ring finger (used by the right hand) or the index finger (used by the left hand), and when the hand is placed on the wide-body mouse, the five fingers are in a relaxed state; the third side face and the fourth side face of the mouse widening device make contact with the inner side faces of the thumb and the little finger for relaxing the hand, the thumb and the little finger are in the relaxed state when the hand is placed on the mouse widening device, and fatigue, ache and lesion of the thumb, the little finger and related muscles are relieved. The thumbs and the little fingers can contract inwardsand stretch outwards to