In a brake controlling device (20), a separating valve (60) is provided in a main flow path (45) for interconnecting a first liquid pressure circuit and a second liquid pressure circuit. When an abnormality detecting section detects an abnormality relating to brake fluid pressure, a controlling section sets the separating valve (60) to a closed state. A leakage suppressing section performs leakage suppressing processing for suppressing entry of a brake fluid, which is in the first liquid pressure circuit, into the second liquid pressure circuit after the separating valve (60) is set to the closed state. A leakage suppressing section sets a master cut valve (64) to a closed state to perform the leakage suppressing processing.