▎ 摘　　要

NOVELTY - Producing low-layer graphene having 2-9 layers comprises first heat treatment by adding graphite to normal methyl-2-pyrolidone (NMP) at 200-210 degrees C, stirring for 1-10 hours, second heat treatment step of cooling the first heat-treated graphite to -10 to 10 degrees C and mechanically exfoliating the heat-treated graphite. USE - The low-layer graphene is useful PTC constant temperature heating element and as a flexible planar heating element in e.g. automobile seats or a nano structure requiring precise temperature control. ADVANTAGE - The low-layer grapheme: secures excellent PTC characteristics and has excellent heating characteristics; reduces power consumption; prevents damage to the heating element due to heat collection; reduces the risk of fire; has high-efficiency; and manufactures heating device of excellent quality. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) PTC constant temperature heating element; (2) a heating device comprising PTC constant temperature heating element; and (3) planar heating element.