The present invention provides 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 an upper part, an injection hole for filling with the cleaning solution is formed in the lower part, and an injection hole cover for closing the injection hole after injection is attached; 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.