A fixing support is adapted to detachably fix a case onto a target object. The fixing support includes a fixing base, a rotary base, a rotary member and an engaging member. The rotary base is adapted to be assembled to the target object. The rotary member is rotatably disposed in the fixing base, and is fixed to the rotary base so as to rotate with the rotatory base on a rotational axis with respect to the fixing base. The engaging member is movably disposed inside the fixing base to be moved to a releasing position and an engaging position with respect to the fixing base according to the rotation of the rotary member. The engaging member has an engaging portion, and the engaging member is adapted to pass through the engaging hole. When the engaging member is moved to the engaging position from the releasing position with respect to the fixing base, the engaging portion engages a shoulder part of the engaging hole. In addition, a fixing module includes the aforesaid case and the aforesaid fixing support.