Microporous carbons were produced by carbonizing and activating bamboo (phyllostachys heterocycla). Carbon dioxide was used as an activating agent. Also the activated carbons were produced using bamboo carbons with less potassium fractions. The potassium fractions are mainly distributing in the middle lamella that connects the adjacent cell walls of bamboo. The micropore distribution became sharper for the carbon produced using bamboo carbon with smaller potassium fractions and controlling the yield of activated carbon no less than 70%. It seems that potassium fractions in the middle lamella will accelerate the activation reaction, and then the micropore distribution tends to be broader when the activation reaction reaches the middle lamella.