Abstract: Ferrous sulfate dosemeter (Fricle dosemeter) is developed for the measurement of the absorbeddose in water, in ~(60)Co radiation field. The reproducibility is less than 1%, and the long--term stabilityof the dosementer had been examined over two years. The uncertainties caused by possible errors are es-timated, and the calculated total uncertainty is ±2.1 % (95% confidence level) while dose rangingfrom 40 to 400 Gy.