Haro was founded in 1926 by Hans Roggenbuck (and derives its name from the initial letters of his name) in the district of Pomerania in Frömsdorf. Later the production was transferred to Frankenstein. The production was centered in the economic pens featuring mostly glass nib. It is not clear if glass nibs were first introduced by this company, or by the Spors created in the United States by Roggenbuck cousin, or has other origins, but it is certainly the distinguishing feature of this company production.
The Haro production had a moderate success due to the glass nib, especially for the characteristic to enable writing on multiple layers of carbon paper, widely publicized by the company. The nib was also corrosion resistant for inks and had very little costs, making the pen cheap. The main drawback still remained, beyond the mechanical fragility, that of a much more rapid consumption of the tip, in addition of course to the writing rigidity.
First fountain pens were hard rubber safety, slim and straight form, in two sizes distinguished by the inscription "Haro I" or "Haro II" on the barrel. Later production used both lever filler and button filler. In 1937 the Haro, as one of the first companies to jump into the economic production market, gave rise to the publication of a newspaper called "Haro-Winkle". In this period the production shifted to celluloid colored pens (blue, green and black pearl striated) using the piston filler.
After the WWII, Silesia was occupied by the Russian and in 1946 "Hans Roggenbuck" was expelled from East Germany, going to live in Bad Merghentheim where he resumed the business with a company for fountain pens repairs, but in 1948 re-founded a factory in Regensburg, resuming the production of glass nib fountain pens, to which were joined also pens with ordinary steel and gold nibs, passing to the use of plastic resins.
Having foreseen the effects of the success of the ballpoint pen, in the 50s the Haro changed market sector, focusing on the production of paper and stationery. The company still exists and is run by the founder's sons.