Disclosed are an image monitoring apparatus and method for displaying a lung ventilation impedance image and a lung perfusion impedance image based on impedance data measured at a thorax of a subject, and a reference image based on a biometric signal, in which impedance data based on voltage measured at the thorax of the subject is separated into lung ventilation impedance data and lung perfusion impedance data, and dynamic bloodstream change data in a heart and blood vessels by electrical impedance tomography (EIT); and a lung ventilation impedance image, a lung perfusion impedance image, and a heart and blood vessel impedance image, which are obtained by the separation, and a reference image based on a biometric signal sensed at a part of the subject targeted to be examined are displayed according to a pathological condition of the subject.