An extracorporeal circulation device having high safety without increases in the circuit scale and the power consumption includes a main control unit responsible for control of a motor drive circuit so as to yield a blood flow rate per unit time set by a user. The motor drive circuit applies a drive signal corresponding to the set blood flow rate to a motor. A sub-control unit configured by a field programmable gate array (FPGA) detects the drive signal applied to the motor and monitors whether or not the drive signal falls within an allowable range corresponding to the set blood flow rate. If the drive signal outside the allowable range is applied, the main control unit is deemed to be in an abnormal state and the main control unit is completely stopped. Then, the sub-control unit takes over the subsequent processing.
