Provided an electronic device including a semiconductor memory unit. The semiconductor memory unit includes: a plurality of storage cells each including a variable resistance element of which resistance is changed in response to a current flowing across the variable resistance element and a selecting element coupled to one end of the variable resistance element; a plurality of word lines corresponding to the respective storage cells and each coupled to a selecting element of a corresponding storage cell; a first line coupled to one ends of the plurality of storage cells; a second line coupled to the other ends of the plurality of storage cells; a voltage adjuster configured to adjust the voltage levels of back bias voltages of the selecting elements of the plurality of storage cells; and an access control unit electrically coupled to the first and second lines and passing an access current to a selected storage cell among the plurality of storage cells.