A phase change memory device includes a plurality of word lines arranged in a row direction and a plurality of bit lines arranged in a column direction. A plurality of reference bit line and a plurality of clamp bit lines are arranged in the column direction. A cell array block including a phase change resistance cell is arranged where a word line and a bit line intersect. A reference cell array block is formed where a word line and the reference bit line intersect. The reference cell array block is configured to output a reference current. A clamp cell array block is formed where a word line and a clamp bit line intersect. The clamp cell array block is configured to output a clamp current. A sense amplifier is connected to each of the bit lines and is configured to receive a clamp voltage and a reference voltage.