Loop-mediated isothermal amplification (LAMP) has several advantages: this technique involves gene amplification under isothermal conditions using only one high-specificity enzyme; the amplification efficiency is so high that large quantities of pyrophosphoric acid are formed as a by-product of DNA synthesis; furthermore, the results can be judged directly on the basis of turbidity. On the other hand, a PCR requires approximately 3.5-4.0 hours. The LAMP method is faster than the PCR method and is also relatively inexpensive. In the present study, we modified the composition of the reaction solutions to reduce the LAMP reaction time; more specifically, a thickener, either polyethylene glycol 8000 or 20000, was added. These results showed that the LAMP method was faster than the original method, and it is able to detect both turbidity and fluorescence. In conclusion, the LAMP reaction could be performed within 20 minutes when reaction mixture supplemented with a thickener was used. This method can be used for tests in various fields such as the diagnosis of hereditary disease and identification of viral infections as point-of-care testing.