In a programmable logic device, switching speed is improved by preventing the bit line potential from going excessively close to ground even when large numbers of word line connections to the ground conductor are made. In addition, bit line pull up to logic 1 is effected more rapidly (without retarding bit line pull down to logic 0) by having two transistors connected in parallel with one another between the reference potential source and the bit line. One of these transistors is on all the time providing a relatively small leakage current. The other transistor is on only while the bit line is at logic 0, thereby speeding pull up to logic 1 and then shutting off so as not to impede subsequent return to logic 0.