A device for measuring and detecting brake dust particles, comprising - a housing for defining a brake mount space in which a brake to be tested can be installed; - a fan system with a supply air duct and an exhaust air duct, which are each connected to the brake mount space, for guiding an airflow through the brake mount space; - an extraction unit arranged within the exhaust air duct for picking up brake dust particles at a measuring point; - a particle measuring unit for measuring the number and/or the size of the brake dust particles; and comprising - a conveying unit for guiding and conveying the brake dust particles from the extraction unit to the particle measuring unit; wherein - the supply air duct has an outlet through which air can be supplied to the housing; - the housing is impermeable to brake dust particles; - the outlet of the supply air duct provided on the housing and an inlet of the exhaust air duct provided on the housing are arranged opposite to each other; characterized in that - the length of the flow path of the airflow and thus the distance between the rotation axis of the brake and the extraction unit depends on the size of the cross section of the exhaust air duct; - the exhaust air duct consists of a non-corrosive, electrically conductive material; - the exhaust air duct is dimensioned in such a manner that its free diameter at its inlet on the housing is not smaller than 70% of the diameter of the brake disc to be tested; and wherein - the distance between the rotation axis of the brake to be tested and the measuring point amounts to 10 to 20 times the diameter of the exhaust air duct. - a housing for defining a brake mount space in which a brake to be tested can be installed; - a fan system with a supply air duct and an exhaust air duct, which are each connected to the brake mount space, for guiding an airflow through the brake mount space; - an extraction unit arranged within the exhaust air duct for picking up brake dust particles at a measuring point; - a particle measuring unit for measuring the number and/or the size of the brake dust particles; and comprising - a conveying unit for guiding and conveying the brake dust particles from the extraction unit to the particle measuring unit; wherein - the supply air duct has an outlet through which air can be supplied to the housing; - the housing is impermeable to brake dust particles; - the outlet of the supply air duct provided on the housing and an inlet of the exhaust air duct provided on the housing are arranged opposite to each other; characterized in that - the length of the flow path of the airflow and thus the distance between the rotation axis of the brake and the extraction unit depends on the size of the cross section of the exhaust air duct; - the exhaust air duct consists of a non-corrosive, electrically conductive material; - the exhaust air duct is dimensioned in such a manner that its free diameter at its inlet on the housing is not smaller than 70% of the diameter of the brake disc to be tested; and wherein - the distance between the rotation axis of the brake to be tested and the measuring point amounts to 10 to 20 times the diameter of the exhaust air duct.