目的：探討夜校生之行為（性行為、使用保險套行為）與健康信念模式四項要素（愛滋自覺嚴重性、愛滋自覺罹患性、使用保險套自覺利益性及使用保險套自覺障礙性）間的關係。方法：採橫斷研究，分層、集束比例抽樣，對桃園縣夜校高中、職二年級生進行問卷調查。結果：2010年9月共回收271份問卷，扣除1份，有效問卷270份。夜校生的愛滋自覺嚴重性分數（3.50）高於愛滋自覺罹患性（2.03），使用保險套自覺利益性（3.08）高於使用保險套自覺障礙性（2.17）。使用保險套自覺利益性：男性（3.04）顯著低於女性（3.19）；使用保險套自覺障礙性：男性（2.31）顯著高於女性（1.92）。有性經驗者共85位（31.6%），95%信賴區間為26.0% ~ 37.1%。性經驗只與學校別（國立、私立）及年齡有關、與健康信念模式四項要素無關，私立及年齡較大者有性經驗的比例較高。最近3個月有性行為者共52位，發生性行為時每次都會使用保險套者及不會使用保險套者各佔36.5%，有時會、有時不會使用保險套佔26.9%。使用保險套情形在學校別、性別、年齡間，皆未達統計顯著意義，與使用保險套自覺利益性及障礙性，達統計顯著意義。結論：夜校生認為愛滋是一個嚴重的疾病，卻認為自己罹患愛滋的可能性不高。男性在使用保險套自覺利益性顯著低於女性，使用保險套自覺障礙性顯著高於女性。性行為與健康信念模式四項要素無關，但使用保險套行為卻與使用保險套自覺利益性、障礙性有關。

Purpose: To study the association between behavior (sexual behavior and condom use) and the four constructs (perceived susceptibility, perceived severity, perceived benefits, perceived barriers) of health belief model (HBM) among grade 11 students in night schools.Methods: A cross-sectional study design and sampling procedures of stratified cluster probability proportional to size in Taoyuan were used to obtain the samples. Grade 11 students were asked to anonymously complete a questionnaire.Results: In September 2010, there were 270 valid samples. The mean score of perceived severity of contracting HIV (3.50) was higher than that of perceived susceptibility of contracting HIV (2.03). The mean score of perceived benefits on condom use (3.08) was higher than that of perceived barriers on condom use (2.17). The mean score of perceived benefits on condom use was significantly lower in male (3.04) than that in female (3.19); but the mean score of perceived barriers on condom use was significantly higher in male (2.31) than that in female (1.92). A total of 85 students (31.6%, 95% confidence interval between 26.0% and 37.1%) were sexually experienced. Being sexually experienced was significantly associated with school type (private vs. public) and age, but not related with the four constructs of HBM. Students in private schools or older students had higher proportion of being sexually experienced. Among 52 students who had sex within last 3 months, the proportion of condoms use while having sex was 36.5% for the persistent users, 36.5% for the never users, and 26.9% for the occasion users. The practice of condom use was not associated with school type, gender and age, but significantly related with 2 constructs (perceived benefits and perceived barriers of using condom) of HBM.Conclusion: Night school students recognize HIV/AIDS is a severe disease, but they think their risk of contracting HIV being low. Male perceives lower benefits on condom use than female does, and male perceives higher barriers on condom use than female does. Sexual experience was not associated with the four constructs of HBM, but condom use was associated with the two constructs (benefits and barriers) of HBM.