There is provided a copper alloy sheet including 1.0 to 3.5 mass % Ni, 0.5 to 2.0 mass % Co, and 0.3 to 1.5 mass % Si, a Co/Ni mass ratio being 0.15 to 1.5, an (Ni+Co)/Si mass ratio being 4 to 7, and a balance being composed of Cu and an unavoidable impurity, wherein in observation results of a crystal grain boundary property and crystal orientation by EBSP measurement, a density of twin boundaries among all crystal grain boundaries is 40% or more and an area ratio of crystal grains with Cube orientation is 20% or more, on a rolled surface.