An over-current protection device includes a first electrode layer, a second electrode layer, and a resistance material disposed between the first and second electrode layers. The first electrode layer includes a first groove pattern formed on and through the first electrode layer. The first groove pattern is configured to separate the first electrode layer into a plurality of connected regions. The second electrode layer includes a second groove pattern formed on and through the second electrode layer. The second groove pattern is configured to separate the second electrode layer into a plurality of connected regions. The first and second groove patterns are further configured to be formed in an interlaced manner that when the first and second electrode layers are overlapped, the first and second groove patterns form a plurality of independent regions, which divide the resistance material into a plurality of electrically isolated and parallel connected units.