In the field of weak magnetic field measurement, fluxgates have higher performance than other magnetic measurement devices. However, it is difficult to reduce fluxgate noise for miniaturized fluxgates. We present a new micro-fabricated iron core structure for a micro-fluxgate in this paper. The magnetization distribution near the edge of each iron core can be improved by adjusting the size and density of the striped array iron core. To investigate the magnetic characteristics of the striped array iron core and its effect on fluxgate noise, we increased the width of each iron core in the striped array core from 30 to 90 µm in 10 µm steps and the adjacent interval width of the striped array iron core from 25 to 45 µm in 5 µm steps. To measure the noise performance of the fluxgate, we used the striped array iron core to construct a flat structure fluxgate. The signal measurement showed that the noise of the fluxgate was related to the adjacent interval width of the striped array iron core, whereas the noise of the striped array iron core was lower than that of a permalloy film with the same total length, width, and thickness as the striped array iron core. The decrease in noise in the flat structure fluxgate was due to the transverse anisotropic field generated by the magnetostatic coupling effect between the striped array iron cores, which readily induced the coherent rotation of the magnetic domains in the magnetization process. The coherent rotation weakened the incoherent jump, the main source of Barkhausen noise, in the domain wall displacement.