A novel flow type electrochemical immuno sensing system using 3-D comb electrodes, which enables high-speed enzyme immunoassay on a single microchip, has been developed. A trap-and-release system of magnetic beads and a sheath flow sorting system are integrated on the chip. The integrated system realizes repeatable sample preparation and sensing. Using this system, AFP detection in the range from 25ng/mL to 500ng/mL was obtained within 30 minutes. This system can be applied widely for high sensitive enzyme immunoassays.