A light-emitting diode array comprising a conductive layer formed on a substrate, pluralities of separate light-emitting portions formed on the conductive layer, a first groove formed in the conductive layer to divide the light-emitting portions to blocks, a first electrodes formed on at least part of an upper surface of each light-emitting portion, a second electrode formed directly on the conductive layer in each block, switching common wirings separately connecting the first electrodes and first bonding pads each connected to each common wiring, first bonding pads each connected to each common wiring, and second bonding pads each connected to each second electrode, the first bonding pads and the second bonding pads being arranged longitudinally in a row, and a ratio of the number of the first bonding pads to the number of the second bonding pads being 1:n (n≧3).