For indoor air quality at a newly built apartment before move-in, we monitored formaldehyde and VOCs and assessed human exposure and probabilistic health risk. We selected 801 newly built apartments all over the country. The results of the research on the condition show the mean concentrations of formaldehyde 294㎍/㎥, 210(median) 1497㎍/㎥(maximum), benzene 6㎍/㎥, (4 and 92㎍/㎥), toluene 1003㎍/㎥(773 and 5013㎍/㎥), ethylbenzene 120㎍/㎥, (62 and 1192㎍/㎥), xylene 287㎍/㎥(138 and 2723㎍/㎥) and styrene 64㎍/㎥, (42 and 531㎍/㎥). Formaldehyde from carcinogen and toluene and xylene from non-carcinogen were assessed the risk for human health. The excess cancer risk of formaldehyde for human beings between carcinogens is per 1.36 of average 1000 persons. This implies that it is over a level per 1.00 of 1000 persons demanding active risk reduction. Hence, we strongly need the active reduction plan and accurate source assumption. Among a variety of factors affecting indoor air quality for householders, closing construction or density of indoor air processing additional interior construction and indoor area, indoor air quality with a variety of districts show significant. The excess cancer risk for human beings of formaldehyde between carcinogens is per 1.36 of average 1000 persons. Non-carcinogen toxicity rate for human-beings with toluene and xylene among non-carcinogens is over HQ 1 from Seoul to local area. keywords：Newly-built apartment house, Indoor air, VOCs, Health risk assessment