Abstract: The present invention discloses an apparatus and a method for controlling fluid flow in or into a well. The apparatus includes at least one housing (3m, 3g, 3w) having an inlet (5) and at least one outlet (7, 7?), one of which is arranged in a top portion or a bottom portion of the housing (3m, 3g, 3w) when in a position of use, and a flow control means (9m, 9g, 9w) disposed within the housing (3m, 3g, 3w). The flow control means (9m, 9g, 9w) has a density that is higher or lower than a density of a fluid to be controlled and a form adapted to substantially block the outlet (7, 7?) of the housing when the flow control means (9m, 9g, 9w) is in a position abutting the outlet (7, 7?).