PURPOSE: A filter device for a drainpipe with a dehydration function is provided to effectively prevent a drainpipe from clogging by filtering all kinds of foreign materials. CONSTITUTION: A filter device(1) for a drainpipe with a dehydration function comprises a case member(100), a filter net member, and a dehydration unit. The case member has an installation space and a detachable knob(110). The filter net member is located inside the installation space to be separated from the inner wall of the case member and filters foreign materials from sewage flowing through a drainpipe(400) connected to the top surface of the case member. The dehydration unit rotates the filter net member and dehydrates foreign materials filtered inside the filter net member.
