A cell controller having excellent productivity is provided. A cell-con 80 has 12 ICs IC-1 to IC-12 mounted on a substrate, and these ICs detect voltages of respective cells constituting a cell pack, perform capacity adjustment on the respective cells, and are mounted two by two on rectangular longer sides of a rectangular continuous straight line L-L′ defined on a substrate from the IC-1 on a highest potential side to the IC-12 on a lowest potential side continuously in order of potential differences of the corresponding cell packs. Distances between the rectangular shorter sides of the rectangular continuous straight line L-L′ are the same. On the cell-con 80, between the IC-1 to IC-12 having different ground voltages, each of the ICs has signal output terminals connected to signal input terminals of a lower order IC respectively in an electrically non-insulated state.