Disclosed herein are an apparatus and a method for detecting a crack. The apparatus includes a power supply unit, a sensor module, and a signal reception module. The power supply unit supplies power. The sensor module receives the input power from the power supply unit, and outputs sensing power corresponding to the magnetic field of an object to be measured. The signal reception unit converts the sensing power output from the sensor module into a quantitative value, and computes the distribution of the magnetic field. The sensor module includes a first sensor array configured to detect magnetic field vectors in a direction vertical to a sensor surface, and a second sensor array placed on the first sensor array in an overlapping manner and configured to detect magnetic field vectors in a direction lateral with respect to the sensor surface.