A machine tool brake device of a portable machine tool includes at least one magnetic-field-type brake unit that is configured to brake a spindle and/or a machining tool when the magnetic-field-type brake unit is in at least one braking position. The machine tool brake device further includes at least one spindle immobilization unit that is configured to immobilize the spindle when the spindle immobilization unit is in at least one immobilization position. The machine tool brake device also includes at least one activation unit that is configured to transfer the magnetic-field-type brake unit into the braking position and to enable an automatic transfer of the spindle immobilization unit into the immobilization position.