A substrate for biochips, which does not induce autofluorescence, which can immobilize a biologically relevant substance(s) easily, which can prevent the undesirable spread of a liquid spot which is added dropwise on the biochips when using the biochips, in which the adhesion between a carbon-containing layer and an aluminum material is high, and which can be produced at lower cost than the known substrate for biochips; a method for producing the substrate; and a biochip including the substrate are disclosed. The substrate for biochips comprises a carbon-coated aluminum material, wherein the carbon-coated aluminum material comprises an aluminum material and a carbon-containing layer formed on at least one surface of the aluminum material, and further comprises an interposing layer which is formed between the aluminum material and the carbon-containing layer, and which interposing layer contains aluminum element and carbon element.