In this study, the combustion characteristics of Hinoki Cypress Louver were measured after performing pressure impregnation with aqueous solution of boric acid, borax, and ammonium phosphate. The characteristics measured include ignition time, critical heat flux, and mass loss rate by incident hear flux (25, 30 and 50 kW/m 2 ). The samples used for the test were 100 × 100 × 10 mm, and the 5 min variation for each incident heat flux was measured 3 times. The results show that the ignition time for incident heat flux of 25 kW/m 2 showed a delay effect of 17.4 to 21.3% except for Type C-H. There was no significant difference at 35 and 50 kW/m 2 in the average mass loss rate in Types A-H and D-H, which had lower rates than Type N-H, which was predicted to be higher than that of Type N-H (10.7 kW/m 2 ) by 38.22 to 60.46%. It is thus expected that at the time of initial primary fire, there would be a delay effect against fire spread.