A weighing machine having a weighing platform includes a detection unit for outputting a detection voltage depending on a load acting on the measuring platform; a first data generation unit for A-D converting the detection voltage to generate first data; a second data generation unit for A-D converting the detection voltage to generate second data; and a control unit which stops operating the second data generation unit and monitors the first data in a standby state, switches from the standby state to a measurement state when the control unit senses that an object is placed on the weighing platform, then stops operating the first data generation unit and operates the second data generation unit, and outputs the measured weight of the object according to the second data. The first data generation unit consumes less power but has a lower A-D conversion precision than the second data generation unit.