PURPOSE: To provide a micro-bulb which has a high sealing property when a lead-in port and a lead-out port are cut off.

CONSTITUTION: This micro-bulb is composed of a glass 2 in which a lead-in port 5 and a lead-out port 6 are formed, an Si substrate 1 which has a movable part 1a, and a glass 3 which has an electrode 4, and an impurity is ion-implanted to the movable 1a to form a high hardness part 7. Since the hardness difference between the high hardness part 7 and the glass 2 is large, the adhesion degree when the movable part 1a makes contact with the glass 2 is increased.