To provide a heavy-metal absorbing fiber structure, using a material in nature as an absorbent and excellent in cleaning efficiency and handling.

The heavy-metal absorbing fiber structure consists of synthetic fibers and contains clay mineral allophane, wherein the clay mineral allophane is kneaded with the synthetic fibers or is added to the synthetic fibers by post processing. As a polylacetic-acid based fiber is used as the synthetic fiber, the heavy-metal absorbing fiber structure has excellent biodegradability and can be used in the form of a membrane.