A water treatment apparatus comprising: a head including an inlet portion into which water flows, an outlet portion from which water is discharged externally, and a connection portion connected to the inlet portion and the outlet portion; and a water treatment unit connected to the connection portion, including a plurality of water treatment sections (321, 322), coupled to the head, and configured such that a portion of the water flowing into the inlet portion passes through the plurality of water treatment sections (321, 322) sequentially, the remainder of the water passes through only a portion of the plurality of water treatment sections (321, 322), and the water flows to the outlet portion together, wherein the water treatment unit includes an inlet/outlet member having an inflow portion into which water flows from the head and an outflow portion through which water is discharged to the head, the inflow portion includes a plurality of first inflow apertures and a plurality of second inflow apertures, and the outflow portion includes a plurality of outflow apertures, the plurality of first inflow apertures and the plurality of second inflow apertures are spaced apart from each other by a predetermined interval, are formed in a circumference of a virtual circle on the inflow portion, and have diameters of which the sizes are decreased in a single direction, the head comprises a head unit including the inlet portion, the outlet portion, and the connection portion; and a flow guide portion guiding the water flowing into the inlet portion to flow into the water treatment unit, and guiding the water treated by the treatment unit to flow into the outlet portion, the flow guide portion includes a passage forming member including an inflow passage having an open lower portion connected to the inflow portion and connected to the inlet portion, and an outflow passage connected to the outlet portion and the connection portion; and an opening/closing member rotatably provided on the passage forming member and including a plurality of opening/closing apertures (222a, 222b) formed therein to open or close the plurality of first inflow apertures or the plurality of second inflow apertures according to a rotating location of the opening/closing member, and the water treatment unit further includes a housing connected to the inlet/outlet member, including the first water treatment section and the second water treatment section, and configured such that a portion of the water flowing into the inflow portion passes through the first and second water treatment sections (321, 322) sequentially, the remainder of the water passes through only the second water treatment section, and the water flows together to the outflow portion. a head including an inlet portion into which water flows, an outlet portion from which water is discharged externally, and a connection portion connected to the inlet portion and the outlet portion; and a water treatment unit connected to the connection portion, including a plurality of water treatment sections (321, 322), coupled to the head, and configured such that a portion of the water flowing into the inlet portion passes through the plurality of water treatment sections (321, 322) sequentially, the remainder of the water passes through only a portion of the plurality of water treatment sections (321, 322), and the water flows to the outlet portion together, wherein the water treatment unit includes an inlet/outlet member having an inflow portion into which water flows from the head and an outflow portion through which water is discharged to the head, the inflow portion includes a plurality of first inflow apertures and a plurality of second inflow apertures, and the outflow portion includes a plurality of outflow apertures, the plurality of first inflow apertures and the plurality of second inflow apertures are spaced apart from each other by a predetermined interval, are formed in a circumference of a virtual circle on the inflow portion, and have diameters of which the sizes are decreased in a single direction, the head comprises a head unit including the inlet portion, the outlet portion, and the connection portion; and a flow guide portion guiding the water flowing into the inlet portion to flow into the water treatment unit, and guiding the water treated by the treatment unit to flow into the outlet portion, the flow guide portion includes a passage forming member including an inflow passage having an open lower portion connected to the inflow portion and connected to the inlet portion, and an outflow passage connected to the outlet portion and the connection portion; and an opening/closing member rotatably provided on the passage forming member and including a plurality of opening/closing apertures (222a, 222b) formed therein to open or close the plurality of first inflow apertures or the plurality of second inflow apertures according to a rotating location of the opening/closing member, and the water treatment unit further includes a housing connected to the inlet/outlet member, including the first water treatment section and the second water treatment section, and configured such that a portion of the water flowing into the inflow portion passes through the first and second water treatment sections (321, 322) sequentially, the remainder of the water passes through only the second water treatment section, and the water flows together to the outflow portion.