Mesophase pitch carbon (MPC) is one of the possible carbonaceous materials as an anode for rechargeable lithium ion batteries. The MPC thin film electrodes were fabricated by modifying reticulated-nickel substrates with a quinoline-soluble part of MPC. We have studied the electrochemical insertion/extraction properties of lithium ion into/from the MPC-based carbon, focusing on the effects of heat-treatment temperature (700-1000 degrees C). Potential excursion experiments show that there are two different mechanisms for extraction of lithium ions; one can be attributed to deintercalation from a graphitized part and the other to extraction from the ungraphitized part of the carbon film.