A semiconductor time switch includes a cell portion and an electron booster. The cell portion contains parallel linear semiconductor layers provided on a substrate as active areas, first and second linear conductor layers alternately formed on the linear semiconductor layers through a gate insulating film as control gates and extending so as to cross the linear semiconductor layers, and floating gates inserted into respective intersections of the linear semiconductor layers and the first linear conductor layers, and coupled to the first linear conductor layers through an inter-gate insulating film. The electron booster is provided on the substrate and includes a MOS transistor having a booster gate electrode connected to the second linear conductor layers. Both ends of the linear semiconductor layers are connected to first and second I/O terminals of the switch, respectively.