In order to prevent a twin-type brake force regulator, having a control tappet and a beam of balance, from performing its pressure reduction function, an electromagnetic locking device that avoids high cost and great expenditure in material is provided. The locking device includes an electric coil, magnet armature and locking member. The locking member is attached to the magnet armature and positioned in a radial position relative to a control piston such that the locking member can be placed in positive engagement with the control tappet. In a preferred embodiment, the locking member has a U-shaped fork with an inner diameter conformed to the control tappet. An advanced position, that is the position in which the control tappet is locked by the locking member, is defined by the position of the magnet armature when the coil is energized. A retracted position of the locking member, in which the control tappet is released, results when the magnet armature is reset, with the coil deenergized. The result is that the twin-type brake force regulator is suitable for use in anti-lock brake systems, because the pressure reduction function is deactivated as long as the anti-lock function is performed and will not be activated until the anti-lock function is disabled.