A filter device has a filter housing (10) receiving a first filter element (12), through which a medium may flow in a given direction, and has a bypass device (22). Along with the first filter element (12), a second filter element (32) is provided. The filter elements are arranged in series, one behind the other, in the direction of flow. When the bypass device (22) is activated, the second filter element (32), immediately following in the direction of flow, filters the medium. The second filter element thus takes over the main filtration of the medium on actuation and operation of the bypass device, since the first filter element is essentially no longer available for a filtration process due to the bypass device.