The Implicit Association Test (IAT) is known as a useful measure of implicit attitude. Recent study had shown that the features of the stimulus items influence the IAT effects (Bluemske & Friese, 2006; Govan & Williams, 2004). We tested whether the stereotypic stimulus items would influence the effects of a gender attitude IAT. Study 1 preliminarily showed that female participants exhibit strong implicit ingroup biases related to gender, but male participant do not. Study 2 showed that the effects of gender attitude IATs were moderated by the stereotypicality of the stimulus items. This study demonstrated that the effects of gender attitude IATs in which stereotypic items were used reflect the effects of gender attitudes and gender stereotyping.