To provide a copper alloy sheet excellent in the balance of strength and electroconductivity and excellent in the balance of strength and bending workability also. A copper alloy contains predetermined amount of Cr, Ti, and Si so as to satisfy a mass ratio of the Cr to the Ti: 1.0<=(Cr/Ti)<=30, and a mass ratio of the Cr to the Si: 3.0<-(Cr/Si)<=30, the remainder including copper and unavoidable impurities, in which 70% or more out of total amount of Cr, Ti and Si contained in the copper alloy is precipitated, a number of piece of precipitates with 300 nm or more circle equivalent diameter observed by a SEM in a region of 25 [mu]m in the thickness direction from the surface of the copper alloy 40 [mu]m in the cross-sectional direction in a cross section in the width direction of the copper alloy is 50 pieces or less, and an average circle equivalent diameter of precipitates with less than 300 nm circle equivalent diameter observed by a TEM on the surface of the copper alloy is 15 nm or less.