In the Japan Atomic Energy Agency (JAEA), exposures doses to fingertips can be significant in radiological decontamination at the facilities with mixture fields of beta and gamma (X) rays. The radiation doses to fingertips have been measured by ring type dosemeters equipped with thermoluminescence dosemeters (TLD) in JAEA. We applied small Optically Stimulated Luminescence (OSL) elements to the ring type dosemeter, which has the advantages in the use for long term and repeating in dose measurements comparing to the TLDs. The dose evaluation method with the new ring type dosemeters was established with studies on the characteristic of the OSL dosemeters by irradiation examinations and Monte Carlo simulations. In this report, we introduce the outline and the dose evaluation method of the new ring type dosemeter which we applied.