1. This study was aimed to clarify the internal structure of home range in the Meadow Bunting Emberiza cioides inhabiting the cultivated fields of Odagiri near Nagano City. The investigation was made 1966 to 1968, most intensely in 1967.2. As many as Meadow Buntings found within a study area of 2.25ha (150m×150m) were color ringed. The population density was 2.7 birds per ha in 1966 and 1967, 2.2 in 1968, which were three times as high as their density in the river-side habitat.3. The 'time-mapping' method of Nakamura (1969) was adopted to measure home ranges, and it was confirmed that six 'one-hour mappings' obtained at any time of the day or season suffice to know the size, shape and center of the home range.4. The average size of the home range of E. cioides in Odagiri was 6.150m2 (0.615ha., δ=1, 689.9).5. The number of home range in the study area decreased yearly according to the change of the habitat. But same arrangement of the home ranges was maintained with high stability.6. The structure of home range was analysed with the distribution of activity loci of a male. In the early breeding season the male had a center of high activity density near the middle of the home range, but with the abvance of season, his activity was more centered closer to the nest and another sub-center was formed near the nest.7. This was supported by the actual observation of the movement of the male. In the beginning of breeding season he showed a tendency to be near the nest and went out to the periphery of the home range in a radial fashion, but this shape gradually changed.8. The distribution of the density of song activity loci almost coincided with that of the density of activity, but there were some spots where the song density was rather high. These are self-abvertisement posts against adjacent individuals, and this reflects the social character of the song activity.9. There were five kinds of territorial behaviors in E. cioides: singing, chasing, actual fighting, confronting and displacement activity.10. By analysing the spots where these territorial behaviors occurred within the home range, it was made clear that the home range of E. cioides under high population density had an encircling structure consisting of a center where the owner never let other individuals enter, and surrounding three zones, where it may win, resist, or defeated against others.11. The width of these zones was not uniform, being either narrow or wide, owing to the circumstance. It was narrow at the spots where the birds could easily memorize it and wide at the spots where there was no striking landmarks.12. The boarder of territory of E. cioides was settled with the balance of defensive intensity against the adjoining individuals.13. Territory in E. cioides well coincided with the song advertisement area.14. From these facts, E. cioides is a typical territorial bird.15. The finding that the home range in E. cioides would retain such a compact internal structure even under high population density, suggests that Emberiza group has at least two ecological lines, one a group that includes E. schoeniclus and E. yessoensis which could become semi-colonial and the other represented by strict territorial E. cioides and others.