Abstract: A modular shelving unit includes at least three upright posts spaced apart from each other for supporting a shelf between them. At least one of the at least three posts includes at least two tubular members and at least one interconnecting member for detachably interconnecting adjacent, tubular members via attaching means. The at least two tubular members each have opposite edges and an inner circumferential wall defining annular inclined surfaces. The annular inclined surfaces are radially and outwardly inclined, as they advance to adjacent edges of the opposite edges. The interconnecting member has an outer circumferential wall with opposite end portions and a flange-like stopper radially and outwardly projecting from the outer circumferential wall. The adjacent tubular members are interconnected to the interconnecting member via the attaching means with mutually facing edges of the adjacent tubular members abutting each other.