A brake apparatus comprising: a hydraulic-pressure source configured to supply a plurality of wheel cylinders (8a, 8b, 8c, 8d) with a brake fluid pressure corresponding to a brake pedal operation by a driver; a first fluid passage (11P, 13P) configured to fluidically communicate the hydraulic-pressure source with a first wheel cylinder (8a, 8d) that is at least one of the wheel cylinders (8a, 8b, 8c, 8d); a second fluid passage (11S, 13S) configured to fluidically communicate the hydraulic-pressure source with a second wheel cylinder (8b, 8c) that is another of the wheel cylinders (8a, 8b, 8c, 8d); a first control valve placed in the first fluid passage to be located between the first wheel cylinder (8a, 8d) and the hydraulic-pressure source; a second control valve placed in the second fluid passage to be located between the second wheel cylinder (8b, 8c) and the hydraulic-pressure source; a first hydraulic-pressure sensor placed in the first fluid passage and configured to detect a hydraulic pressure existing between the hydraulic-pressure source and the first wheel cylinder (8a, 8d); a second hydraulic-pressure sensor placed in the second fluid passage and configured to detect a hydraulic pressure existing between the hydraulic-pressure source and the second wheel cylinder (8b, 8c); characterized in that a fluid-leakage detecting unit configured to supply a brake fluid to the first and second fluid passages (13P, 13S) through the hydraulic-pressure source, switch the first and second control valves (23P, 23S) alternately between open and closed positions more than once, and detect a brake-fluid leakage in the first or second fluid passage (11P/11S) on the basis of magnitudes of detection values detected by the first and second hydraulic-pressure sensors (92P, 92S) during the open-close switching. a hydraulic-pressure source configured to supply a plurality of wheel cylinders (8a, 8b, 8c, 8d) with a brake fluid pressure corresponding to a brake pedal operation by a driver; a first fluid passage (11P, 13P) configured to fluidically communicate the hydraulic-pressure source with a first wheel cylinder (8a, 8d) that is at least one of the wheel cylinders (8a, 8b, 8c, 8d); a second fluid passage (11S, 13S) configured to fluidically communicate the hydraulic-pressure source with a second wheel cylinder (8b, 8c) that is another of the wheel cylinders (8a, 8b, 8c, 8d); a first control valve placed in the first fluid passage to be located between the first wheel cylinder (8a, 8d) and the hydraulic-pressure source; a second control valve placed in the second fluid passage to be located between the second wheel cylinder (8b, 8c) and the hydraulic-pressure source; a first hydraulic-pressure sensor placed in the first fluid passage and configured to detect a hydraulic pressure existing between the hydraulic-pressure source and the first wheel cylinder (8a, 8d); a second hydraulic-pressure sensor placed in the second fluid passage and configured to detect a hydraulic pressure existing between the hydraulic-pressure source and the second wheel cylinder (8b, 8c); characterized in that a fluid-leakage detecting unit configured to supply a brake fluid to the first and second fluid passages (13P, 13S) through the hydraulic-pressure source, switch the first and second control valves (23P, 23S) alternately between open and closed positions more than once, and detect a brake-fluid leakage in the first or second fluid passage (11P/11S) on the basis of magnitudes of detection values detected by the first and second hydraulic-pressure sensors (92P, 92S) during the open-close switching.