(amend) A battery pack state parallel-monitoring device having a battery pack configured with a plurality of battery cells, a cell monitoring unit for measuring a state of the plurality of battery cells, a Battery Monitoring Integrated Circuit BMIC for generating a diagnostic signal indicating a state of the battery pack through the cell monitoring unit, a communication unit for transmitting/receiving data between the BMIC and a main Micro-controller Unit MCU and data between the BMIC and an auxiliary MCU, the main MCU for receiving the diagnostic signal, and the auxiliary MCU for receiving the diagnostic signal and transmitting/receiving data of the main MCU, the battery pack state parallel-monitoring device comprising: data lines configured to transmit/receive data from the BMIC to the main MCU through the communication unit; parallel lines connected in parallel to the data lines; and a communication monitoring unit connected to the parallel lines to monitor data transmitted/received from the BMIC to the main MCU through the communication unit and transfer the monitored data to the auxiliary MCU; a control unit configured to control an operation state of the communication monitoring unit; and a storage unit configured to pre-store operation execution time information indicating a time consumable by the main MCU which has received the diagnostic signal from the BMIC to start execution of an operation corresponding to the diagnostic signal wherein the control unit determines whether the main MCU performs the operation within the time indicated by the operation execution time information when the main MCU has received the diagnostic signal from the BMIC through the communication unit, generates an operation execution command signal for instructing the auxiliary MCU to immediately perform the operation corresponding to the diagnostic signal when the main MCU does not perform the operation within the time indicated by the operation execution time information as a result of the determination, and transfers the execution command signal to the auxiliary MCU via the communication monitoring unit so that the operation is performed. data lines configured to transmit/receive data from the BMIC to the main MCU through the communication unit; parallel lines connected in parallel to the data lines; and a communication monitoring unit connected to the parallel lines to monitor data transmitted/received from the BMIC to the main MCU through the communication unit and transfer the monitored data to the auxiliary MCU; a control unit configured to control an operation state of the communication monitoring unit; and a storage unit configured to pre-store operation execution time information indicating a time consumable by the main MCU which has received the diagnostic signal from the BMIC to start execution of an operation corresponding to the diagnostic signal wherein the control unit determines whether the main MCU performs the operation within the time indicated by the operation execution time information when the main MCU has received the diagnostic signal from the BMIC through the communication unit, generates an operation execution command signal for instructing the auxiliary MCU to immediately perform the operation corresponding to the diagnostic signal when the main MCU does not perform the operation within the time indicated by the operation execution time information as a result of the determination, and transfers the execution command signal to the auxiliary MCU via the communication monitoring unit so that the operation is performed.