Background: The problem of the influence of magnetic fields (FMs) on the growth and development of common bean plants is still far from being fully explained due to its complicated physical nature and the geometry of the seeds. FMs can practically penetrate through living organisms. Aim: The present work aimed to determine the effect of the presowing FM stimulation of common bean seeds on plant growth and development elements. Material and Methods: The present study was based on a field experiment carried out between the years 2015 and 2017 in Żyznów (N 49°81′, E 21°84′, 239 m above sea level). The experiment was carried out using three repetitions of the randomized block method. The experimental factor was the amount of exposure to FM seed stimulation: (I) 15 s, (II) 30 seconds, and (III) the control object without seed stimulation. The plant material of the study was a common bean: cv. Gold Saxa. Results: The biostimulation of the sources with an FM improved the germination energy, strength, and capacity of the seeds. The presowing FM stimulation of the common bean seeds favourably affected the fresh weight of the first and fifth leaves but did not affect their dry weight. The leaves’ collection dates measured the new first and fifth plates and their dry weight content. The collection dates of the leaves determined the level of the fresh weight of the first and fifth leaves and the content of their dry weight. Conclusions: The biostimulation of the seeds with the FM contributed to a higher germination capacity, energy, and strength of the common bean seeds. The highest level of the leaves’ fresh weight was achieved during full flowering, and the highest dry matter content of the leaves was found in the phase of pod setting.