The utility model relates to a spring force-balancing mechanism for a cashbox, and the spring force-balancing mechanism comprises a box body and a carrying plate located in the box body, wherein a first slide plate and a second slide plate are vertically connected to the both ends of the carrying plate respectively; a support plate which is vertical with the carrying plate, a first spring, a second spring, a third spring and a fourth spring are installed in the box body; a first guide wheel group and a second guide wheel group are arranged at the upper end and lower end of the support plate respectively; one end of each of the first spring and the second spring is connected to the first slide plate; one end of each of the third spring and the fourth spring is connected to the second slide plate; the other end of each of the first spring and the third spring is connected with the support plate around a part of the first guide wheel group and the second guide wheel group; and the other end of each of the second spring and the fourth spring is connected with the support plate around all the first guide wheel group and the second guide wheel group. The spring force-balancing mechanism disclosed by the utility model is simple in structure, high in space utilization rate due to the condition that cash can be fully filled in the box body, and constant in a pushing force for pushing the cash.