A terahertz detector and a method of manufacturing a terahertz detector, wherein the terahertz detector including a substrate (2) and at least one detection unit. Each detection unit includes: a channel material (1) arranged on the substrate, two electrodes (3, 4) respectively in ohmic contact with both ends of the channel material (1) in a longitudinal direction, and a three-dimensional grapheme (5) in direct or indirect thermal contact with the channel material (1).