An integrity check device includes a register array processing circuitry which generates a current cyclic redundancy check (CRC) parity value by sequentially performing a CRC calculation on a plurality of safety sensitive data, stores a reference CRC parity value, outputs a check result signal indicating whether an error occurs by activating a first path and by comparing the current CRC parity value with the reference CRC parity value when the plurality of safety sensitive data are maintained and when an operation of updating the reference CRC parity value is unnecessary, and updates the reference CRC parity value to the current CRC parity value by activating a second path when at least one of the plurality of safety sensitive data is intentionally changed and when the operation of updating the reference CRC parity value is necessary.