A semiconductor device includes a first memory block including a first memory string, a second memory block including a second memory string, a common source line commonly coupled to the first memory block and the second memory block, a first bit line coupled to the first memory string, a second bit line coupled to the second memory string, a first page buffer for accessing the first memory string through the first bit line, and a second page buffer for accessing the second memory string through the second bit line. The first bit line and the first page buffer are electrically connected to each other when the first memory block is selected.