An impedance measuring apparatus is disclosed. The impedance measuring apparatus includes an input current generator configured to generate a sinusoidal input signal of a carrier frequency, a first electrode configured to apply the sinusoidal input signal to an object which has an impedance, a second electrode configured to receive an amplitude modulated signal from the object, a first amplifier configured to amplify the received amplitude modulated signal and output a first amplified signal, a baseline signal subtractor configured to subtract a baseline signal generated based on the first amplified signal from the amplitude modulated signal and output a subtraction modulated signal, an analog-to-digital converter (ADC) configured to convert the subtraction modulated signal to a digital modulated signal, and an impedance measurer configured to measure the impedance based on the digital modulated signal.