A filter for removing dust from fluids, which comprises fibers bonded each other with a binder and hot-pressed, having a fiber density of 0.01 to 0.1 at the fluid inlet side and a fiber density of 0.05 to 0.5 at the fluid outlet side with a continuous fiber density gradient and having a uniform distribution of fiber material in direction of thickness, and a process for the production thereof. The filter is particularly useful as an air filter for automobiles or air conditioners.