The invention provides a firework setting-off device. The device comprises a plurality of firework launching pipes, a launching pipe angle fixing assembly and a support. The firework launching pipes are used for internally arranging firework products. The launching pipe angle fixing assembly comprises a first plate, a second plate and a bottom plate, the first plate, the second plate and the bottom plate are parallel to one another, are obliquely arranged relative to the horizontal plane and are arranged from top to bottom in sequence. The first plate and the second plate are provided with a plurality of through holes for inserting of the of firework launching pipes. The contact ends of the inserted firework launching pipes can make contact with the bottom plate, and after the firework launching pipes are inserted in the launching pipe angle fixing assembly, a pattern formed by the free ends, not in contact with the bottom plate, of the firework launching pipes is a similar pattern with the amplified size relative to a pattern formed by the contact ends of the firework launching pipes. The device is safe in setting off, accurate in pattern, easy and convenient to use and low in cost. Especially, the device has the accurate firework setting off positioning function, and the effect obtained after setting off is kept to be highly consistent with the expected pattern.