[en] The day by day evolution was investigated of the June to July 1974 proton-flare region's local magnetic field, composed originally of at least two individual local fields, and the functioning of its ''magnetic centres of activity'' was studied. Two such main and at least one ''secondary'' centres were found to which the development of new magnetic fluxes could be related. The tendency of the complex magnetic field to form one simple bipolar field, properly inclined toward the equator, was estimated as being one of the main reasons for the changes of the observed field topology. During these changes the positive field of the eastern region extended toward the west to join the same polarity field of the western region and became the main leading field and the western negative polarity field shifted towards the east to join the eastern fie--ld of like polarity which took over the role of the main following field. (author)