This study focused on the effects of stratified structure due to segregation of particle size and graded bedding in clean sand deposits on their liquefaction characteristics. A well-graded clean sand was sieved and separated into four components with different ranges of particle size, and then deposited alternatively to create stratified structure in specimens. Undrained triaxial compression tests in monotonic loading conditions and cyclic triaxial loading tests were performed on these stratified samples as well as the uniformly mixed samples of the same sand. It was observed that the liquefaction resistance of the stratified specimens was larger than the uniform specimens. These test results indicate a possibility of underestimation of liquefaction resistance of deposits with laminar structure in situ, if it is evaluated in the laboratory using homogeneously reconstituted samples.