Disclosed is an apparatus for inspecting a defect of a display panel. The apparatus for inspecting includes the display panel that displays an image, an input sensor that is disposed on the display panel and senses an input applied from outside, a sensor driving part that drives the input sensor, and an inspection part that is connected with the sensor driving part, sets a frequency of the input sensor to an inspection frequency, and detects the defect of the display panel based on a change in a jitter occurring when the input sensor is driven at the inspection frequency. The inspection frequency includes a harmonic frequency of a driving frequency of the display panel.