This study has purported to identify whether the training to vitalize the right-hemisphere brain functions contributes to the enhancement to cognitive laterality of the right- hemisphere brain functions and the mathematical problem solving ability. The subjects of this experiment are arbitrarily sampled 242 second year high school girl students. Through the CLB test the subjects are divided into the left-hemisphere brain dominance group (95 persons) and the right-hemisphere brain dominance group (90 persons) and 60 persons from each group have been assigned to the experimental group and the control group. The finding derived from this experiment are as follows; 1) The Effect on the Right Brain Performance Ability by the Right Brain Training. As a result of searching into the influence of the right brain function training on the right brain performance ability, it is revealed that the experimental group of the better performing left brain types indicated 3.6 points(T score) higher than the control group after the conduct off the examinations, showing statistically meaningful differences [t(58)=2.03, p=.047J, while the better performing right brain types, even thought the experimental group scored 1.6 points(T score) higher than the control group, reflected not of statistically significant differences [t(58)= 1.05, p=.183]. Consequently, the effect of the right brain training on the right brain performance was reflected only in the better left brain performance type. 2) The Effect of the Right Brain Training on the Right Brain Preference. As a result of searching into the effect of the right brain training on the right brain preference, the experimental group of the better performing right brain type scored 1.3 points higher than the control group after the test but of no statistical significance [t(58)=.33. p=.280]. There was also no significant differences between the experimental group and control group of the better performing left brain type [t(58)=.33, p=.743]. Consequently, there was no effect apparent by the right brain function training on the right brain preference. 3) The Effect of the Right Brain Function Training on the Mathematical Problem Solving Ability. Investigation into the effect of the right brain function training on the mathematical problem solving ability revealed that the experimental group of the better performing left brain types scoring 1.27 points higher than the control group indicating the statistically meaningful differences after the execution of the test [t(58) =2.87, p=.006] while the better performing right brain types indicated no difference between the experimental group and the control group [t(58) = 1.46, p=.149]. Consequently, the effect of the right brain training on the mathematical problem solving ability was apparent only in the better performing left brain types. Conclusions derived from the foregoing findings are that functions of both the left and right brains are necessary in the creative problem solving. For the development of such ability, therefore, the whole brain education is very important in enabling the balanced development of the left and right brain functions.