PURPOSE: To prevent brake control from suddenly becoming inoperative by stopping the anti-skid brake control when anti-skid brake control is not being operated or all plural read-out data vary from each other.

CONSTITUTION: Data which are stored in a RAM 4-2 are read out and computed, and the computed result is outputted to a solenoid driving circuit 5 to drive a solenoid valve 6 for brake control of wheels when anti-lock brake is necessary. At this time, in order to check the malfunction of a memory device, identical computed results are stored in plural different areas of the RAM 4-2, and the data which are stored in different areas are read out later to compare and judge whether they are identical or not. If all the data in the plural RAM areas do not coincide with each other during anti-skid brake(ABS) control, the data are not reliable, so the ABS control device is turned off for a change into a normal brake operation.