Sinter deposit in a distributing pipe used for about fifteen years in Misasa radioactive hot springs was investigated. The results were as follows; 1. The metal elements in this deposit were quaIi. tatively analysed by spectraspan plasma emission spectrophotometry (SPES), by fluorescent X-ray spectrometry, and following elements were detected; B, Na, Mg, AI, K, Ca, Mn, Fe, Cu, Zn, As, Sr, Ba and Pb. 2. The metal elements in this deposit were quantatively analysed by SPES and atomic absorption spectrophotometry, and following elements were determined; Fe : 508.7, As: 26.40, Ca: 7.85, Mn : 2.00, Al : 1.80, Na: 1.60, Zn: 1.33, K: 0.80, Cu: 0.67, Sr: 0.47, Mg: 0.35, Ba: 0.33 and B : 0.30 mg per gram. The color of this deposit was red brown, and the main component was ferric oxide. 3. Radioactive elements in this deposit were detected by autoradiography and radioluxography. Among the radioactive elements, concentration of radium was 320.5×10(-12)g/g (313.0×10(-12)Ci/g).