The utility model relates to the technical field of cigarette production, in particular to an opening expanding device of cigarette case equipment. The guide body and the first opening supporting plate are sequentially arranged at the front end of the cigarette case opening supporting plate, the guide body and the first opening supporting plate are both of a trapezoid structure, the second opening supporting plate is of a frame-shaped structure and is fixed to the outer portion of the cigarette case opening supporting plate, and an arc-shaped groove is formed in the side, close to the first opening supporting plate, of the second opening supporting plate. After the fixed cigarette case is conveyed to the opening supporting position through the rotary disc, the air cylinder pushes the cigarette case opening supporting plate to work, the opening of the cigarette case continues to be opened, the shape of the opening part of the cigarette case is fixed, and follow-up cigarette box entering operation is facilitated. The fixing mode designed by the utility model is simpler and more effective, on one hand, the shape of the opening part of the cigarette case can be conveniently and quickly fixed, so that follow-up equipment can conveniently and accurately feed cigarettes into the cigarette case, on the other hand, the cigarette case opening supporting plate can be directly replaced for different styles of cigarette cases, and maintenance is basically not needed; and the maintenance cost in the production and use process can be reduced.