Disclosed herein is a functional material having the function of detecting a predetermined substance or the like present in a sample with high accuracy even when the amount of the sample is small, and a method for producing the functional material. The functional material includes a channel part 10 that allows a liquid to pass therethrough, and the channel part 10 is made of a water-permeable material 11 containing a water-impermeable material 12. The water-impermeable material 12 is placed between pieces of the water-permeable material 11, and therefore voids 10h can be formed between the water-impermeable material 12 and the water-permeable material 11. That is, a network of the voids 10h can be formed in the channel part 10. A liquid sample supplied to the channel part 10 is allowed to move while being allowed to penetrate into the voids 10h. In addition, components other than a desired component can be separated and removed from a mixture present in the liquid sample while the liquid sample is allowed to move. Therefore, a water-absorbing function and a filtering function can be imparted to the channel part 10.