An advance practice before actual trails may affect handgrip strength exertion values in gradually increased demand values. This study aimed to examine effects of an adjustment practice of grip exertion with subjective intensity with 50% of the maximum grip strength on handgrip values in gradually increased demand values and its laterality. Subjects were 20 healthy males (age: 21.2 ± 1.7). The demand values were 20%, 40%, 60% and 80% of the maximum grip. In three pre-practice, each value was immediately fed back to each subject. A relative error(%) between demanded and actual exertion values was used as an evaluation variable. In a result of two-factor variance analysis ( demand values x dominant hand/non-dominant hands), a significant interaction (p<0.05) was found. Multiple comparisons showed that a significant difference was found only in the non-dominant hand and the 20% demand value had a larger error than the other demand values (40%, 60%, and 80%). In addition, it was significantly larger in the non-dominant hand than in the dominant hand. In conclusion, when performing an advance with 50% subjective intensity of the maximum grip, an error in the 20% demand value is larger than that in the other demand values in the non-dominant hand and in the dominant hand.