Disclosed is a biomolecule detector and a detection method using the same. The biomolecule detector includes a biomolecule chip having a substrate and a slit formed therein. Biomolecules are immobilized on at least a portion of the edges of the slit. A light source directs incident light toward the biomolecule chip, and a screen receives an image formed by a portion of the incident light passing through the slit. The biomolecule detector is small and portable, yet its capability for detecting a target biomolecule is quick, accurate and simple. The simple structural features of the biomolecule detector enable mass production.