PURPOSE: To prevent bedewing on the outer surface of a valve by forming stem penetration parts over and under a cylinder. forming a drive manipulation/ mounting part in the upper stem penetration part in a single piece structure so that a core is formed, and covering the pressure bearing part of this core with a material having a low thermal conductivity such as resin.

CONSTITUTION: A butterfly valve concerned is for use in the pipings for a cooling, refrigerating facility, etc. wherein a core 10 equipped with stem penetration parts 12, 13 over and under a short cylinder 11 is embedded in the valve body 1, and among the stem penetration parts the one 12 is provided with a drive manipulatin/mounting part 15 in which an actuator, handle, etc. are mounted. The core 10 is made from a stainless steel plate or cylinder having a low thermal conductivity through a press working or a holding processing, and the cylinder 11 is bored with punch holes 20... in any shape. The cylinder 11 as a pressure bearing part of this core 10 and the drive manipulation/ mounting part 15 are covered 14, 16 with a synthetic resin having a low thermal conductivity such as special-reinforced polyamide resin.