by weight of cuo and 1 10 by weight of zno in which pbo sio 2 al 2 o 3 b 2 o 3 cuo and zno amount to at least 95 by weight this is because mixing a second glass within the composition of this range with the first glass can further increase the firing capability in addition to decreasing the length effect on tcr and the small variations in resistance values and the tcr on firing the overcoat glass the second glass is used in an amount of 5 40 by weight preferably 10 35 by weight on the basis of the total weight of the composition containing the organic medium the amount is 7 57 by weight preferably 14 50 by weight if based on the total inorganic solids the thick film resistor composition of this invention may further comprise a third glass as a glass binder the third glass is a pbo sio 2 glass with its softening point adjusted to be lower than that of the first glass but higher than that of the second glass for example it has a composition of 65 0 by weight of pbo 34 0 by weight of sio 2 and 11 0 by weight of al 2 o 3 the third glass is used in an amount of 0 30 by weight preferably 5 25 by weight on the basis of the total weight of the composition containing he organic medium the amount is 0 43 by weight preferably 7 36 by weight if based on the total inorganic solids the first second and third glasses may individually contain in addition to the above components.