The invention relates to a magnetic sensor for checking documents of value and an apparatus and a method, wherein there are used a magnetization device for magnetizing a document of value and the magnetic sensor for detecting magnetic signals of the document of value. The magnetic sensor has two sensor lines which have several magneto-sensitive elements with different main sensitivity directions which are oriented in particular perpendicular to each other. The first sensor line selectively detects first magnetic areas of the document of value of a first coercive field strength and the second sensor line selectively detects second magnetic areas of the document of value of a second coercive field strength. Since the differently coercive magnetic areas of the document of value are detected independently of each other, there can be ascertained reliably and independently of each other two magnetic codings from differently coercive magnetic areas, which are arranged on the same document of value.