▎ 摘　　要

Dirac fermions exhibit various characteristic transport phenomena in graphene. Particularly in high magnetic fields, the electronic states of Dirac fermions are quantized into Landau levels, and graphene shows a half-integer quantum Hall effect. Here, we discuss the edge-channel picture in graphene quantum Hall junctions and review experiments on the quantum Hall effect in graphene in-plane unipolar and bipolar junctions.