A substrate inspection apparatus using optical coherence tomography, the apparatus comprising: a first light source configured to radiate an ultraviolet light onto a coated film of a substrate, the coated film being mixed with fluorescent pigments; a first light detector configured to capture fluorescence generated from the coated film onto which the ultraviolet light is radiated, and to obtain a two-dimensional image of the substrate from the fluorescence; a second light source configured to radiate a laser light onto the coated film of the substrate; a second light detector configured to obtain optical interference data generated from the coated film by the laser light; a memory configured to store information indicating a region of interest on the substrate that is predetermined by a user; and a processor configured to: determine among a plurality of regions of the substrate a first region of which thickness is to be measured based on the information indicating the region of interest and the 2D image; control the second light source to radiate a laser light onto the first region, and control the second light detector to obtain optical interference data generated from the first region by the laser light; and derive a thickness of the coated film of the first region based on the optical interference data generated from the first region, wherein the region of interest is a region that includes electrodes of elements on the substrate. a first light source configured to radiate an ultraviolet light onto a coated film of a substrate, the coated film being mixed with fluorescent pigments; a first light detector configured to capture fluorescence generated from the coated film onto which the ultraviolet light is radiated, and to obtain a two-dimensional image of the substrate from the fluorescence; a second light source configured to radiate a laser light onto the coated film of the substrate; a second light detector configured to obtain optical interference data generated from the coated film by the laser light; a memory configured to store information indicating a region of interest on the substrate that is predetermined by a user; and a processor configured to: determine among a plurality of regions of the substrate a first region of which thickness is to be measured based on the information indicating the region of interest and the 2D image; control the second light source to radiate a laser light onto the first region, and control the second light detector to obtain optical interference data generated from the first region by the laser light; and derive a thickness of the coated film of the first region based on the optical interference data generated from the first region, determine among a plurality of regions of the substrate a first region of which thickness is to be measured based on the information indicating the region of interest and the 2D image; control the second light source to radiate a laser light onto the first region, and control the second light detector to obtain optical interference data generated from the first region by the laser light; and derive a thickness of the coated film of the first region based on the optical interference data generated from the first region, wherein the region of interest is a region that includes electrodes of elements on the substrate.