A data storage device configured to store data on malfunction of a robot, the data storage device comprising: a first acquisition unit and a second acquisition unit configured to acquire data at every control period; wherein the first acquisition unit is configured to acquire first data on first malfunction of the robot at every control period; the second acquisition unit is configured to acquire second data on second malfunction of the robot at every control period, the second malfunction is different from the first malfunction and the second data is different from the first data; a first determination unit configured to determine whether or not to store the first data through determining whether or not the first data is equal to or more than a predetermined value of the first data; a second determination unit configured to determine whether or not to store the second data through determining whether or not the second data is equal to or more than a predetermined value of the second data; a memory configured to store the first data and the second data; and a controller configured to when the first determination unit determines at a given control period to store the first data, set a sampling period (Ts) to a first sampling period (t 1), and store the first data in the memory at the first sampling period (t 1) starting from the given control period, and when at another given control period the first determination unit determines not to store the first data and the second determination unit determines to store the second data, set the sampling period (Ts) to a second sampling period (t 2) longer than the first sampling period (t 1), and store the second data in the memory at the second sampling period (t 2) starting from the other given control period. a first acquisition unit and a second acquisition unit configured to acquire data at every control period; wherein the first acquisition unit is configured to acquire first data on first malfunction of the robot at every control period; the second acquisition unit is configured to acquire second data on second malfunction of the robot at every control period, the second malfunction is different from the first malfunction and the second data is different from the first data; the first acquisition unit is configured to acquire first data on first malfunction of the robot at every control period; the second acquisition unit is configured to acquire second data on second malfunction of the robot at every control period, the second malfunction is different from the first malfunction and the second data is different from the first data; a first determination unit configured to determine whether or not to store the first data through determining whether or not the first data is equal to or more than a predetermined value of the first data; a second determination unit configured to determine whether or not to store the second data through determining whether or not the second data is equal to or more than a predetermined value of the second data; a memory configured to store the first data and the second data; and a controller configured to when the first determination unit determines at a given control period to store the first data, set a sampling period (Ts) to a first sampling period (t 1), and store the first data in the memory at the first sampling period (t 1) starting from the given control period, and when at another given control period the first determination unit determines not to store the first data and the second determination unit determines to store the second data, set the sampling period (Ts) to a second sampling period (t 2) longer than the first sampling period (t 1), and store the second data in the memory at the second sampling period (t 2) starting from the other given control period. when the first determination unit determines at a given control period to store the first data, set a sampling period (Ts) to a first sampling period (t 1), and store the first data in the memory at the first sampling period (t 1) starting from the given control period, and when at another given control period the first determination unit determines not to store the first data and the second determination unit determines to store the second data, set the sampling period (Ts) to a second sampling period (t 2) longer than the first sampling period (t 1), and store the second data in the memory at the second sampling period (t 2) starting from the other given control period.