A wheelchair has a chair, an electrical power device, a foot stand, and a control device. The chair has two arm rest frames, and each arm rest frame has a connection board. The electrical power device is detachably connected with the connection boards and has a holding frame, a driving device, and two rear wheels. The holding frame has two holding boards respectively connected with the connection boards by multiple securing assemblies. Each securing assembly has a holding sleeve, a connecting rod, a knob, and a spring. The holding sleeve has multiple abutting ribs. The connecting rod is mounted through the holding sleeve and has a first end and a second end selectively extending into one of the connecting holes defined in a corresponding connection board. The knob is mounted securely around the second end of the connecting rod and has multiple engaging grooves.
