A portable interdental toothbrush comprising: a cleaning solution tube in which a cleaning solution is received to be carried conveniently, an assembly protrusion for discharging the cleaning solution is formed in the upper part; and a brush body in which an assembly hole into which the assembly protrusion of the cleaning solution tube is inserted and assembled is formed in the lower part to be assembled to the assembly protrusion of the cleaning solution tube and a brush fixing portion is fixed in the upper part, wherein a discharge hole for discharging the cleaning solution is formed in a longitudinal direction in the center of the assembly protrusion of the cleaning solution tube, a screw portion is formed in the lower end of an outer surface thereof, and an extended portion from the screw portion is formed such that a support extension is extended; and wherein, in the assembly hole formed in the lower part of the brush body, a negative screw portion is formed in the lower end, a support extension groove is formed in the middle, and a fixing hole is formed in an upper part, and the brush fixing portion is fixed in the fixing hole in the upper part of the brush body, characterized in that an injection hole for filling with the cleaning solution is formed in the lower part, and an inflow hole cover for closing the injection hole after injection is attached; and a brush cover for protecting the brush is covered on an upper part of the brush body, and a planar portion is formed on a part of an outside of the brush body, and a cover planar portion adjacent to the planar portion is also formed on a part of the brush cover inserted into the brush body, so that when the brush cover is rotated once, then the adjacent cover planar portion applies a force to rotate the planar portion of the brush body. a cleaning solution tube in which a cleaning solution is received to be carried conveniently, an assembly protrusion for discharging the cleaning solution is formed in the upper part; and a brush body in which an assembly hole into which the assembly protrusion of the cleaning solution tube is inserted and assembled is formed in the lower part to be assembled to the assembly protrusion of the cleaning solution tube and a brush fixing portion is fixed in the upper part, wherein a discharge hole for discharging the cleaning solution is formed in a longitudinal direction in the center of the assembly protrusion of the cleaning solution tube, a screw portion is formed in the lower end of an outer surface thereof, and an extended portion from the screw portion is formed such that a support extension is extended; and wherein, in the assembly hole formed in the lower part of the brush body, a negative screw portion is formed in the lower end, a support extension groove is formed in the middle, and a fixing hole is formed in an upper part, and the brush fixing portion is fixed in the fixing hole in the upper part of the brush body, characterized in that an injection hole for filling with the cleaning solution is formed in the lower part, and an inflow hole cover for closing the injection hole after injection is attached; and a brush cover for protecting the brush is covered on an upper part of the brush body, and a planar portion is formed on a part of an outside of the brush body, and a cover planar portion adjacent to the planar portion is also formed on a part of the brush cover inserted into the brush body, so that when the brush cover is rotated once, then the adjacent cover planar portion applies a force to rotate the planar portion of the brush body.