There is provided a current measuring apparatus for measuring a first current used for estimating a load torque of the motor. The current measuring apparatus may include a detection unit configured to detect a first voltage, an amplification unit including a first input terminal at which the second signal is input, a second input terminal coupled to a first resistor and a second resistor by which an amplification factor is defined, and an output terminal for outputting a third signal, an input unit configured to input a second voltage at the first input terminal, a storage unit configured to store a third voltage an acquisition unit configured to acquire a fourth voltage, and a calculation unit configured to calculate the first current based on a difference between the third voltage and the fourth voltage.