The present disclosure relates to diagnostic apparatus and method for home appliance which make it easy to diagnose a breakdown of a home appliance, using a signal including product information and outputted from the home appliance, in which a signal is converted in accordance with signal distortion generated in the process of transmitting the output signal or in a terminal, so that the product information of the home appliance is easily extracted, accuracy of a diagnosis result is improved, an after-sales service for a breakdown of the home appliance is easily provided, and reliability of the product is improved by the improvement of accuracy of the diagnosis result.