Provided are an apparatus for training a companion animal for defecation and a method thereof. The apparatus includes a pad storage unit configured to store a defecation pad; a pad treating unit configured to treat the defecation pad by rolling up the defecation pad when the companion animal defecates on the defecation pad provided on a defecation table; an image processing unit configured to photograph the defecation pad and process a photographed image; and a control unit configured to analyze the image processed by the image processing unit to determine whether the defecation pad is used for defecation, wherein the control unit controls an operation of the pad treating unit to treat the used defecation pad and provide a new defecation pad on the defecation table when it is determined that the defecation pad is used for defecation.