An object tracking device adapted to track a target object in a time-series image including a plurality of frames, the object tracking device comprising: a location information acquisition unit for acquiring location information of a target object in a first frame, the target object being a tracked target; a detailed contour model generation unit for generating a detailed contour model in the first frame, on the basis of the location information, the detailed contour model being formed with a plurality of contour points (X1 to Xn) representing a contour of the target object; a search location setting unit for setting a plurality of different search locations (S1 to Sm) in a second frame, the second frame being any one of frames following the first frame; a rough contour model generation unit for identifying a plurality of first associated points (Y1 to Yn) at each search location (S1 to Sm) in the second frame which correspond to locations of the plurality of contour points (X1 to Xn), when the detailed contour model is applied to each search location (S1 to Sm), the rough contour model generation unit being adapted to select a first predetermined number (u) of points out of the plurality of first associated points (Y1 to Yn) as second associated points (Ya1 to Yau), the first predetermined number (u) being fewer than the first associated points (n; Y1 to Yn), and to generate at each search location (S1 to Sm) a rough contour model formed with the second associated points (Ya1 to Yau); a likelihood assessment unit for comparing, at each search location (S1 to Sm), a second image feature amount related to the second associated points (Ya1 to Yau) of the rough contour model in an image of the second frame with a first image feature amount related to one or more of the contour points (X1 to Xn) of the detailed contour model in an image of the first frame which correspond to the second associated points (Ya1 to Yau), thereby assessing likelihoods that the individual search locations (S1 to Sm) in the second frame are a location of the target object; and an object location identification unit (22, 36) for identifying the location of the target object from the plurality of search locations (S1 to Sm), on the basis of the likelihoods determined by the likelihood assessment unit. a location information acquisition unit for acquiring location information of a target object in a first frame, the target object being a tracked target; a detailed contour model generation unit for generating a detailed contour model in the first frame, on the basis of the location information, the detailed contour model being formed with a plurality of contour points (X1 to Xn) representing a contour of the target object; a search location setting unit for setting a plurality of different search locations (S1 to Sm) in a second frame, the second frame being any one of frames following the first frame; a rough contour model generation unit for identifying a plurality of first associated points (Y1 to Yn) at each search location (S1 to Sm) in the second frame which correspond to locations of the plurality of contour points (X1 to Xn), when the detailed contour model is applied to each search location (S1 to Sm), the rough contour model generation unit being adapted to select a first predetermined number (u) of points out of the plurality of first associated points (Y1 to Yn) as second associated points (Ya1 to Yau), the first predetermined number (u) being fewer than the first associated points (n; Y1 to Yn), and to generate at each search location (S1 to Sm) a rough contour model formed with the second associated points (Ya1 to Yau); a likelihood assessment unit for comparing, at each search location (S1 to Sm), a second image feature amount related to the second associated points (Ya1 to Yau) of the rough contour model in an image of the second frame with a first image feature amount related to one or more of the contour points (X1 to Xn) of the detailed contour model in an image of the first frame which correspond to the second associated points (Ya1 to Yau), thereby assessing likelihoods that the individual search locations (S1 to Sm) in the second frame are a location of the target object; and an object location identification unit (22, 36) for identifying the location of the target object from the plurality of search locations (S1 to Sm), on the basis of the likelihoods determined by the likelihood assessment unit.