In an experiment conducted with 17 adults, we investigate the impact of the use of an innovative application we created for iPad (called FINGERS©) on the cognitive workload during 3D geometry problems solving. We compare the cognitive workload (assessed with EEG) related to three supports (paper-and-pencil / polyhedrons / FINGERS©) during 3D geometry problems solving. Results have mainly showed that the use of our application minimizes the cognitive load during 3D geometry problems solving especially for the hardest geometry problems.