A multilayer ceramic electronic device includes a ceramic functional part having a generally rectangular shape in which a plurality of ceramic dielectric layers and a plurality of internal electrodes are laminated alternately in a vertical direction; a pair of cover parts that cover the functional part from top and bottom, respectively; and a pair of side margin parts covering side surfaces of the functional part, respectively, wherein an end portion of an uppermost internal electrode among the plurality of internal electrodes is curved downward to satisfy a≥1 μm and 0.1≤a/b≤0.4, where a is a dimension of the curved end portion in the vertical direction in a cross section taken along a plane perpendicular to the side surfaces, and b is a dimension of the curved end portion in a horizontal direction in said cross section.