Accumulation and fibril formation of amyloid beta (A beta) peptides onto a ganglioside-rich lipid membrane is a cause of neuro-disturbance diseases. To find out a measure for suppressing the nucleation of a seed for amyloid fibrils, the mechanism of the initial binding of A beta to the membrane should be clarified. Molecular dynamics simulations were carried out to investigate the adhesion process of A beta peptides onto a GM1-ganglioside-containing membrane. Multiple computational trials were executed to analyze the probability of occurrence of A beta binding by using calculation models containing a mixed lipid membrane, water layer, and one two, or three A beta s. The simulations demonstrated that A beta peptides approached the membrane after fluctuation in the water layer and occasionally made steady contact with the membrane. Once the steady contact had been established, A beta was unlikely to be detached from the membrane and developed into a more stably bound form. In the stably bound form, neuraminic acids on the GM1 cluster strongly held the side chain of Lys28 of A beta, which caused deformation of the C-terminal region of the A beta. Since the C-terminal region of the A beta peptide contains many hydrophobic residues, its deformation on the membrane enhances the hydrophobic interaction with other A beta peptides. The contact region of two A beta s evolved into a parallel beta-sheet form, and the third A beta was observed to be bound to the complex of two A beta s to make a bundle of A beta peptides. Some key structures involved in the A beta aggregation on the GM1-containing membrane were deduced from the multiple simulations.