The invention discloses a mixed material weighing device and an adding type weighing method and belongs to the bath salt ball production field. The device comprises a mounting rack, and is characterized in that the left end surface of the mounting rack is provided with a connecting plate, the mounting rack is provided with a top plate through the connecting plate, the lower end surface of the top plate is fixedly provided with a weighing sensor
assembly, a first mounting plate is fixedly mounted on the lower end face of the weighing sensor
assembly, a second mounting plate is mounted on the left end face of the first mounting plate, a valve is fixedly mounted on the left end face of the second mounting plate, an upper end opening of the valve is communicated with a material
barrel, and a lower end opening of the valve is communicated with a discharging hole, a third mounting plate is fixedly mounted on the right end face of the first mounting plate, a speed
reducer is fixedly installed on the right end face of the third mounting plate, a motor is fixedly installed on the right end face of the speed
reducer, and an output shaft of the motor is connected with an input shaft of the speed
reducer, and the output shaft of the speed reducer is connected with a valve element in the valve.