A brake control apparatus comprising: a first wheel cylinder (23FR, 23FL) configured to exert braking force on a first wheel; a second wheel cylinder (23RR, 23RL) configured to exert braking force on a second wheel different from the first wheel; a first hydraulic pressure circuit (37, 61, 45a, 41, 42) configured to supply brake fluid from a reservoir to the first wheel cylinder (23FR, 23FL); a second hydraulic pressure circuit (38, 62, 45b, 43, 44) configured to supply the brake fluid from the reservoir to the second wheel cylinder (23RR, 23RL); a manual hydraulic pressure source configured to generate hydraulic pressure in accordance with an amount of brake operation; an isolation valve provided in a main flow channel that brings the first hydraulic pressure circuit (37, 61, 45a, 41, 42) and the second hydraulic pressure circuit (38, 62, 45b, 43, 44) into communication with each other; a problem detection unit configured to detect a problem related to brake fluid pressure; characterized by a control unit configured to bring the isolation valve into a closed state when the problem related to the brake fluid pressure is detected by the problem detection unit, and the hydraulic pressure generated by the manual hydraulic pressure source is supplied to at least the first hydraulic pressure circuit (37, 61, 45a, 41, 42); and a leakage prevention unit configured to perform a leakage prevention process for preventing the brake fluid in the first hydraulic pressure circuit (37, 61, 45a, 41, 42) from flowing into the second hydraulic pressure circuit (38, 62, 45b, 43, 44) after the isolation valve is brought into the closed state by the control unit, wherein the isolation valve is a differential pressure valve that opens when differential pressure across the isolation valve becomes at least a predetermined value P1, and the brake control apparatus further comprises a first fluid pressure detection unit (73, 70) configured to detect brake fluid pressure in the first hydraulic pressure circuit (37, 61, 45a, 41, 42); and a second fluid pressure detection unit (71, 70) configured to detect brake fluid pressure in the second hydraulic pressure circuit (38, 62, 45b, 43, 44), wherein the leakage prevention unit performs the leakage prevention process when differential pressure derived from a detection value by the first fluid pressure detection unit (73, 70) and a detection value by the second fluid pressure detection unit (71, 70) exceeds a predetermined value P2 that is smaller than the predetermined value P1. a first wheel cylinder (23FR, 23FL) configured to exert braking force on a first wheel; a second wheel cylinder (23RR, 23RL) configured to exert braking force on a second wheel different from the first wheel; a first hydraulic pressure circuit (37, 61, 45a, 41, 42) configured to supply brake fluid from a reservoir to the first wheel cylinder (23FR, 23FL); a second hydraulic pressure circuit (38, 62, 45b, 43, 44) configured to supply the brake fluid from the reservoir to the second wheel cylinder (23RR, 23RL); a manual hydraulic pressure source configured to generate hydraulic pressure in accordance with an amount of brake operation; an isolation valve provided in a main flow channel that brings the first hydraulic pressure circuit (37, 61, 45a, 41, 42) and the second hydraulic pressure circuit (38, 62, 45b, 43, 44) into communication with each other; a problem detection unit configured to detect a problem related to brake fluid pressure;