A method of manufacturing an optical fiber tape core wire, comprising: a printing step of causing a plurality of optical fiber wires to run, each optical fiber wire including a silica glass fiber and a resin coating layer of resin coating the silica glass fiber, and using printers, to print markings on the respective optical fiber wires for identifying the optical fiber tape core wire; a colored layer formation step of using a coloring device provided in downstream of the printers in a fiber running direction to form translucent colored layers of different colors on the respective optical fiber wires so as to coat circumferences of the resin coating layer and the markings; a colored layer curing step of using a colored layer curing device provided in downstream of the coloring device in the fiber running direction to cure the colored layers; a tape forming layer formation step of using a tape forming device provided in downstream of the colored layer curing device in the fiber running direction to collectively coat the optical fiber wires with colorless transparent resin into a tape to form a tape forming layer; a tape forming layer curing step of using a tape forming layer curing device provided in downstream of the tape forming device in the fiber running direction to cure the tape forming layer; and a fiber running length adjustment step which includes: measuring respective positions of the markings printed on the respective optical fiber wires in just upstream or downstream of the tape forming device, calculating relative positional shift amounts of the measured position of the respective markings; and adjusting, based on the relative positional shift amounts, running lengths of the respective optical fiber wires from the respective printers to the tape forming device to same lengths so as to align the respective markings of the optical fiber wires at same positions in a width direction of the optical fiber tape core wire. a printing step of causing a plurality of optical fiber wires to run, each optical fiber wire including a silica glass fiber and a resin coating layer of resin coating the silica glass fiber, and using printers, to print markings on the respective optical fiber wires for identifying the optical fiber tape core wire; a colored layer formation step of using a coloring device provided in downstream of the printers in a fiber running direction to form translucent colored layers of different colors on the respective optical fiber wires so as to coat circumferences of the resin coating layer and the markings; a colored layer curing step of using a colored layer curing device provided in downstream of the coloring device in the fiber running direction to cure the colored layers; a tape forming layer formation step of using a tape forming device provided in downstream of the colored layer curing device in the fiber running direction to collectively coat the optical fiber wires with colorless transparent resin into a tape to form a tape forming layer; a tape forming layer curing step of using a tape forming layer curing device provided in downstream of the tape forming device in the fiber running direction to cure the tape forming layer; and a fiber running length adjustment step which includes: measuring respective positions of the markings printed on the respective optical fiber wires in just upstream or downstream of the tape forming device, calculating relative positional shift amounts of the measured position of the respective markings; and adjusting, based on the relative positional shift amounts, running lengths of the respective optical fiber wires from the respective printers to the tape forming device to same lengths so as to align the respective markings of the optical fiber wires at same positions in a width direction of the optical fiber tape core wire. measuring respective positions of the markings printed on the respective optical fiber wires in just upstream or downstream of the tape forming device, calculating relative positional shift amounts of the measured position of the respective markings; and adjusting, based on the relative positional shift amounts, running lengths of the respective optical fiber wires from the respective printers to the tape forming device to same lengths so as to align the respective markings of the optical fiber wires at same positions in a width direction of the optical fiber tape core wire.