A non-volatile semiconductor storage device including a first potential retention line configured to retain a potential corresponding to data read from the memory cell, a second potential retention line configured to retain a reference potential read from the memory cell in which the reference potential is written after the data is read out, a sense amplifier configured to amplify a difference between the potential retained by the first potential retention line and the reference potential for reading out the data from the memory cell, a first offset adjustment circuit connected to the first potential retention line, for adjusting an offset for the potential, a second offset adjustment circuit connected to the second potential retention line, and an offset command signal supply circuit configured to supply a first offset command signal to the first offset adjustment circuit so as to control the offset.