Resistance change type memory

A resistance change type memory comprising:

• first and second drive lines extending in a first direction;
• third and fourth drive lines extending in a second direction intersecting the first direction;
• first and second resistance change elements having one ends connected to the third drive line;
• third and fourth resistance change elements having one ends connected to the fourth drive line;
• a first zener diode having an anode connected to other end of the first resistance change element and a cathode connected to the first drive line;
• a second zener diode having an anode connected to other end of the second resistance change element and a cathode connected to the second drive line;
• a third zener diode having an anode connected to other end of the third resistance change element and a cathode connected to the first drive line;
• a fourth zener diode having an anode connected to other end of the fourth resistance change element and a cathode connected to the second drive line;
• a driver/sinker which supplies a write current to the first resistance change element;
• and
• a write control circuit arranged such that when first data is written to the first resistance change element, the write current is caused to flow in a direction from the first drive line to the third drive line, and when second data is written to the first resistance change element, the write current is caused to flow in a direction from the third drive line to the first drive line,
• wherein when the first and second data are written to the first resistance change element, the write control circuit causes the second drive line to float,
• the write current is set to a first value when the first data is written to the first resistance change element as well as set to a second value when the second data is written to the first resistance change element,
• the first value is such a value that a voltage applied to the first zener diode is made equal to or larger than the zener voltage thereof and a voltage applied to the second or third zener diode is made less than the zener voltage thereof, and
• the second value is such a value that a voltage applied to the fourth zener diode is made less than the zener voltage thereof.