A processing device includes: a plurality of bitcells, each of the plurality of bitcells including: a variable resistor layer including a plurality of active variable resistors and a plurality of inactive variable resistors; an active layer including a plurality of switches configured to control either one of a voltage to be applied between ends of each of the active variable resistors and a current flowing to each of the active variable resistors; and a plurality of metal layers including wires electrically connecting the active variable resistors to the switches, wherein at least one of the plurality of bitcells includes a via penetrating through the variable resistor layer and connecting at least one of the switches to at least one of the active variable resistors.