A filter device for filtering particles from an air stream has an inlet channel through which the air to be purified flows, at least one filter element through which the air can flow and which is interchangeably held in a flow channel, and an outlet channel through which the purified air flows, an insertion chamber which can be closed by a door and from which a filter element can be fed to the flow channel, and an output chamber closable by a closure element, into which a filter element is feedable from the flow channel. The closure element of the output chamber is locked in the closed position via a locking mechanism when the door on the insertion chamber is opened and the output chamber and the insertion chamber are connected to the same flow channel.