A balance shaft module equipped with a dual pump including a main oil pump and a sub-oil pump may include a pump rotor rotatably coupled to a housing, a discharge space formed in the housing for discharging oil in the sub-oil pump, a pulse chamber formed in the housing to increase the discharge space, wherein the oil discharged through the discharge space is merged with the oil flowing through the pulse chamber such that discharge pulse pressure is reduced, and an eccentric washer having a discharging opening space formed by cutting off a portion inward from the outside, wherein the discharge opening space of the eccentric washer is connected to the discharge space to fluid-communicate with the discharge space of the pump rotor.