The present invention relates to a biosensor technique in which multiple types of target substances (biomarkers) contained in saliva or the like are allowed to be simultaneously measured or N samples for one target substance (biomarker) are allowed to be simultaneously measured and reliability of sensed results and high sensitivity are secured. A fluidic channel-based planar biosensor chip, in which a plurality of fluidic channels capable of measuring target substances (biomarkers) are embedded in one flat plate sensor chip and the flat plate sensor chip is measured by a light-emitting element (optical source) and a light-receiving element, and a biomarker measuring apparatus using the same are provided.