A semiconductor device includes: a stack structure including insulating layers and conductive layers, which are alternately stacked; a channel structure penetrating the stack structure; data storage patterns respectively interposed between the conductive layers and the channel structure; blocking patterns respectively interposed between the conductive layers and the data storage patterns; insulating patterns respectively interposed between the insulating layers and the channel structure; and insulative liners interposed between the insulating layers and the insulating patterns, the insulative liners respectively surrounding the insulating patterns.