A nonvolatile semiconductor storage system has multiple nonvolatile semiconductor storage media, a control circuit having a media interface group (one or more interface devices) coupled to the multiple nonvolatile semiconductor storage media, and multiple switches. The media interface group and the multiple switches are coupled via data buses, and each switch and each of two or more nonvolatile chips are coupled via a data bus. The switch is configured so as to switch a coupling between a data bus coupled to the media interface group and a data bus coupled to any of multiple nonvolatile chips that are coupled to this switch. The control circuit partitions write-target data into multiple data elements, switches a coupling by controlling the multiple switches, and distributively sends the multiple data elements to multiple nonvolatile chips.