The proper use of condoms is one of the most effective types of protection against HIV. One of the major factors that negatively affect the use of condoms is embarrassment caused by the purchasing of condoms. To clarify the causes and effects of embarrassment on the purchasing of condoms, 522 undergraduate student volunteers were investigated. The results showed that both males and females experienced two types of embarrassment, 'Basic embarrassment' and 'Awkwardness,' when they purchased condoms. Moreover, structural equation modeling revealed that the purchasing of condoms by males was strongly inhibited due to vagueness in the guidelines of condom-purchasing behavior, and the purchasing of condoms by females was strongly inhibited due to inconsistency with self-image and the purchasing of condoms. Implications of this study for HIV prevention, especially the intervention method of promoting condom purchasing, are also discussed.