An intravenous flow control device includes a flexible drip chamber (20) comprising a fluid entrance (22) and an open bottom (231) a rigid drip assembly (30) secured to the drip chamber (20) and comprising an inner cylinder (31) having a bottom exit (331) and an internal float valve (10) comprising a fastening member (12) including a hollow inner cylinder (121), a plunger (11) slidably disposed through the inner cylinder (121), an upper float member (15) secured to one end of the plunger (11), a lower float member (13) secured to the other end of the plunger (11), and a block member (14) secured to the lower float member (13) for sealingly blocking the exit (331). Fluid flows into the inner cylinder (31) for accumulation so as to float the block member (14), thereby unblocking the exit (331) and moving the plunger (11) upward.
