A diagnosis method of a diagnostic apparatus for a home appliance, the diagnosis method comprising the following steps: driving a camera of the diagnostic apparatus when receiving a diagnosis execution command for the home appliance according to manipulation of an input unit of the diagnostic apparatus; capturing, by the camera, a signal output at a displaying unit of the home appliance as an image signal; outputting the image signal as a preview screen by a displaying unit of the diagnostic apparatus; processing the image data input through the camera by a first image processing unit of the diagnostic apparatus; analyzing the image data processed by the first image processing unit on a per-frame basis by a second image processing unit of the diagnostic apparatus to thereby search a start code, applying a start signal to a diagnostic apparatus controller of the diagnostic apparatus by the second image processing unit in case among image frames inputted in the preview screen one includes a start code; controlling the camera by the diagnostic apparatus controller according to the applied start signal to start video capturing; if the start signal is inputted, discarding, by the first image processing unit, the image data in the preview screen after temporarily storing it and processing further image data input from the camera; if the video capturing starts, analyzing each frame of the further image data inputted from the first image processing unit by the second image processing unit; classifying frames having captured codes to set a valid frame, and discarding the frames not having the captured codes by the second image processing unit; recognizing product information encoded in the captured codes of the home appliance by the second image processing unit; searching an end code by the second image processing unit among the codes recognized by performing per-frame analysis on the processed image data processed by the first image processing unit; applying an end signal to the diagnostic apparatus controller by the second image processing unit in case there is a frame including the end code; if an end signal is applied, applying a capturing end command to the camera by the diagnostic apparatus controller to thereby stop capturing; and storing the further image data in a data unit of the diagnostic apparatus by the first image processing unit if the capturing is complete; and diagnosing the home appliance corresponding to the product information and outputting a diagnosis result by a diagnosing unit of the diagnostic apparatus. driving a camera of the diagnostic apparatus when receiving a diagnosis execution command for the home appliance according to manipulation of an input unit of the diagnostic apparatus; capturing, by the camera, a signal output at a displaying unit of the home appliance as an image signal; outputting the image signal as a preview screen by a displaying unit of the diagnostic apparatus; processing the image data input through the camera by a first image processing unit of the diagnostic apparatus; analyzing the image data processed by the first image processing unit on a per-frame basis by a second image processing unit of the diagnostic apparatus to thereby search a start code, applying a start signal to a diagnostic apparatus controller of the diagnostic apparatus by the second image processing unit in case among image frames inputted in the preview screen one includes a start code; controlling the camera by the diagnostic apparatus controller according to the applied start signal to start video capturing; if the start signal is inputted, discarding, by the first image processing unit, the image data in the preview screen after temporarily storing it and processing further image data input from the camera; if the video capturing starts, analyzing each frame of the further image data inputted from the first image processing unit by the second image processing unit; classifying frames having captured codes to set a valid frame, and discarding the frames not having the captured codes by the second image processing unit; recognizing product information encoded in the captured codes of the home appliance by the second image processing unit; searching an end code by the second image processing unit among the codes recognized by performing per-frame analysis on the processed image data processed by the first image processing unit; applying an end signal to the diagnostic apparatus controller by the second image processing unit in case there is a frame including the end code; if an end signal is applied, applying a capturing end command to the camera by the diagnostic apparatus controller to thereby stop capturing; and storing the further image data in a data unit of the diagnostic apparatus by the first image processing unit if the capturing is complete; and diagnosing the home appliance corresponding to the product information and outputting a diagnosis result by a diagnosing unit of the diagnostic apparatus.