A portable exercise device includes a body has two shafts respectively longitudinally extending therefrom and co-axially aligning with each other. Two rotors and two torsion springs are respectively pivotally sleeved on the two shafts of the body to make the two rotors reciprocally rotate relative to the two shafts. A wrench device and a stretch device respectively securely receive the two rotors for providing two exercise ways to the user.