A holding module, comprising: a body; two first holding members, retractably disposed at two opposite sides of the body along a first direction, and each comprising a first clamping part and a first groove along a second direction, wherein a nonzero angle is included between the first direction and the second direction; a first rotating member, rotatably disposed at the body and comprising two first protrusions separating from each other, wherein the first protrusions respectively protrude to the corresponding first grooves, wherein when one of the first holding members is moved, the corresponding first groove of the one of the first holding members drives one of the first protrusions to rotate the first rotating member and synchronically drives the other first protrusion to push the other first holding member, such that the two first clamping parts approach or depart away from each other; a stopper member, movably disposed in the body, located at a side of the first rotating member and adapted to contacting or departing away from the first rotating member, wherein when the stopper member contacts the first rotating member, the first rotating member is incapable of rotating; wherein the stopper member comprises a switching part and a fixing part connected with each other, and the body has a first casing comprising a through slot, wherein the fixing part is located in the first casing, the switching part passes through the through slot and exposes to outside of the first casing, and the through slot extends along a direction perpendicular to the protruding direction of the switching part, and the switching part is adapted to move along the through slot, such that the fixing part contacts or departs away from the first rotating member; and the holding module being characterized by a swiveling member, disposed in the first casing and near the fixing part, and comprising a limiting hook capable of being turned to stay on a moving path of the switching part, so as to retain a relative position of switching part in the through slot. a body; two first holding members, retractably disposed at two opposite sides of the body along a first direction, and each comprising a first clamping part and a first groove along a second direction, wherein a nonzero angle is included between the first direction and the second direction; a first rotating member, rotatably disposed at the body and comprising two first protrusions separating from each other, wherein the first protrusions respectively protrude to the corresponding first grooves, wherein when one of the first holding members is moved, the corresponding first groove of the one of the first holding members drives one of the first protrusions to rotate the first rotating member and synchronically drives the other first protrusion to push the other first holding member, such that the two first clamping parts approach or depart away from each other; a stopper member, movably disposed in the body, located at a side of the first rotating member and adapted to contacting or departing away from the first rotating member, wherein when the stopper member contacts the first rotating member, the first rotating member is incapable of rotating; wherein the stopper member comprises a switching part and a fixing part connected with each other, and the body has a first casing comprising a through slot, wherein the fixing part is located in the first casing, the switching part passes through the through slot and exposes to outside of the first casing, and the through slot extends along a direction perpendicular to the protruding direction of the switching part, and the switching part is adapted to move along the through slot, such that the fixing part contacts or departs away from the first rotating member; and the holding module being characterized by a swiveling member, disposed in the first casing and near the fixing part, and comprising a limiting hook capable of being turned to stay on a moving path of the switching part, so as to retain a relative position of switching part in the through slot.