From 1988 to 1993,we studied anti-invading methods against the brown marmorated stink bug, Halyomorpha mista, in houses at several locations in Toyama Prefecture, Japan, where a great number of the bugs in overwintering flight has been observed every year. The "slit-trap" was proved to be effective as an attractant for the bugs. When several traps were set around a building, the number of invading bugs into the building apparently decreased. The application of concentrated cyphenothrin and the laying of a cyphenothrin-treated polyethylene sheet to window-frames were also effective to prevent the invasion of the bugs. These preventive measures were almost 100% effective in reinforced concrete buildings such as modern hotels, whereas the number of invading bugs to wooden houses only slightly decreased. Covering wooden houses with cyphenothrin-treated nets was effective to prevent the invasion of the bugs. The application of repellent (Deet) to window-frames was also effective.