For the safe handling of isopropyl alcohol, the explosion limits were investigated. The lower flash points, upper flash points, fire point, and AITs(autoignition temperatures) by ignition time delay for isopropyl alcohol were experimented. By using literature data, the lower and upper explosion limits of isopropyl alcohol were recommended as 2.0 and 12.0 vol%, respectively. The lower flash points of isopropyl alcohol were experimented $12{sim}14^{circ}C$ by using closed-cup tester and $18{sim}19^{circ}C$ by using open cup tester. And the upper flash points of isopropyl alcohol was experimented $38^{circ}C$ by using Setaflash closed-cup tester. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 apparatus was $463^{circ}C$.