The present invention relates to a patrol device and a patrol path planning method. The patrol device includes an operating unit configured to establish a plurality of patrol paths, each of which has an Average Patrol Omission (APO) value and an Average Patrol Quality (APQ) value, and to determine an optimum patrol path from the plurality of patrol paths according to the APO value and the APQ value; and a moving unit configured to move along the optimum patrol path. The method includes providing a plurality of patrol paths, each of which has an Average Patrol Omission (APO) value and an Average Patrol Quality (APQ) value; and evaluating the plurality of patrol paths according to the respective APO values and the respective APQ values so as to select an optimum patrol path therefrom.