A data storage device that performs a process of writing to a memory a plurality of measured data sets received in time series includes: a nonvolatile memory divided in a plurality of blocks to which the measured data is written; and a write control section that performs a processing including successively writing N sets of the measured data to a given block in the nonvolatile memory, and then successively writing next N sets of the measured data to another block, wherein the write control section judges whether or not the N sets of measured data lastly written to the given block of the nonvolatile memory and another N sets of measured data obtained after the N sets of measured data lastly written to the given block contain data with a value outside a predetermined range, writes new measured data to the given block such that the N sets of measured data lastly written to the given block are not overwritten when the data with a value outside the predetermined range is included, and writes new measured data to the given block such that at least one of the N sets of measured data lastly written to the given block is overwritten when the data with a value outside the predetermined range is not included.