Here, we demonstrate a novel process to convert TiO2 nanotubes into ferroelectric nanohoneycombs, comprised of vertically aligned PbTiO3 nanotubes. Tube bottom opening process enabled effective infiltration of lead acetate precursor into the nanotubes. Nanohoneycombs, which were converted via additional lead supplement process, showed uniform conversion and well-defined ferroelectric properties with the effective piezoelectric coefficient of approximately 20 pm/V, which was measured by piezoresponse force microscopy.