This copper alloy contains at least zirconium in an amount of not less than 0.005% by weight and not greater than 0.5% by weight, includes a first grain group including grains having a grain size of not greater than 1.5 .mu.m, a second grain group including grains having a grain size of greater than 1.5 .mu.m and less than 7 .mu.m, the grains having a form which is elongated in one direction, and a third grain group including grains having a grain size of not less than 7 .mu.m, and also the sum of .alpha. and .beta. is greater than .gamma., and .alpha. is less than .beta., where .alpha. is a total area ratio of the first grain group, .beta. is a total area ratio of the second grain group, and .gamma. is a total area ratio of the third grain group, based on a unit area, and .alpha.+.beta.+.gamma.=1.