A semiconductor unit with memory devices, each of the memory devices includes: a first semiconductor layer; second and third semiconductor layers; a first dielectric film and a first conductive film; first, second, and third electrodes electrically connected to the second semiconductor layer, the third semiconductor layer, and the first conductive film, respectively, the third electrode being electrically connected to the first electrode. In the memory devices, when a voltage equal to or higher than a predetermined threshold value is applied between the first and second electrodes, a filament that is a conductive path electrically linking the second and third semiconductor layers is formed in the region between the second and third semiconductor layers, and thereby, writing operation of information is performed.