A motion estimation method comprising: determining a global motion type of an entire previous frame of a current frame based on motion vectors of the previous frame, wherein the possible global motion types include a type indicating a frame having no global motion, eight translational motion types, two rotational motion types, a zoom-in motion type, and a zoom-out motion type; determining whether the determined global motion type is the type indicating the frame having no global motion; if the determined global motion type is not the type indicating the frame having no global motion, dividing the current frame into a plurality of sections; setting a search area for a motion block included in the current frame; determining to which section the search area for the motion block belongs; setting a preferential area by dividing, depending on the section to which the search area for the motion block belongs, the search area into a preferential area having a high priority and other areas having low priority based on the global motion type of the previous frame, for preferentially searching for a motion vector in the search area; searching for the motion vector within said preferential area; wherein the determining of the global motion type of the entire previous frame comprises: determining direction classes to which the motion vectors of the previous frame belong, wherein a direction class is one of eight direction classes formed by dividing 360 degrees into eight sections; determining for each of a plurality of sections of the previous frame corresponding to the plurality of sections of the current frame a representative direction, the representative direction being the direction class having the highest frequency among the values of the direction classes in the section; determining the global motion type of the entire previous frame based on the respective representative directions of the respective sections of the previous frame. determining a global motion type of an entire previous frame of a current frame based on motion vectors of the previous frame, wherein the possible global motion types include a type indicating a frame having no global motion, eight translational motion types, two rotational motion types, a zoom-in motion type, and a zoom-out motion type; determining whether the determined global motion type is the type indicating the frame having no global motion; if the determined global motion type is not the type indicating the frame having no global motion, dividing the current frame into a plurality of sections; setting a search area for a motion block included in the current frame; determining to which section the search area for the motion block belongs; setting a preferential area by dividing, depending on the section to which the search area for the motion block belongs, the search area into a preferential area having a high priority and other areas having low priority based on the global motion type of the previous frame, for preferentially searching for a motion vector in the search area; searching for the motion vector within said preferential area; wherein the determining of the global motion type of the entire previous frame comprises: determining direction classes to which the motion vectors of the previous frame belong, wherein a direction class is one of eight direction classes formed by dividing 360 degrees into eight sections; determining for each of a plurality of sections of the previous frame corresponding to the plurality of sections of the current frame a representative direction, the representative direction being the direction class having the highest frequency among the values of the direction classes in the section; determining the global motion type of the entire previous frame based on the respective representative directions of the respective sections of the previous frame. determining direction classes to which the motion vectors of the previous frame belong, wherein a direction class is one of eight direction classes formed by dividing 360 degrees into eight sections; determining for each of a plurality of sections of the previous frame corresponding to the plurality of sections of the current frame a representative direction, the representative direction being the direction class having the highest frequency among the values of the direction classes in the section; determining the global motion type of the entire previous frame based on the respective representative directions of the respective sections of the previous frame.