[en] Equipments and procedures used to obtain the data of atmospheric ⁸⁵Kr concentration are described. The apparatus for the separation and purification of krypton from air are consisted of charcoal and molecular sieve cold trap and a titanium furnace. The purity of the elutriator is detected by chromatographic sensor. All the system are particularly made of metal to eliminate the breakage problems encountered frequently with glass system. One to three cubic meter of air sample can be processed and reduced to several milliliter of krypton. Rapid and accurate dissolving method of krypton in toluene and xylene is devised. Optimum condition for ⁸⁵Kr measurement in liquid scientillation counting are determined by the use of the gas diluted from LMRI (CEA) ⁸⁵Kr standard. The absolute measurement of ⁸⁵Kr activities is carried out by the extrapolated zero-bias technique. Krypton samples separated from the air collected at Himeji-city in 1972, 1975 and 1976 are analyzed. The data show that atmospheric concentration of ⁸⁵Kr remained roughly constant (14 pCi/m³ air) during these years. (author)