Plate with flow channel

A plate comprising:

• a main body;
• a flow channel provided in the main body and configured to flow inert gas therein;
• a cover configured to cover a surface of the main body where the flow channel is formed;
• a buried member buried in an opening of the flow channel, the buried member including
• a buried portion fixed to the flow channel and made of dense ceramic having a porosity equal or lower than 20%, and
• a flow portion held by the buried portion and configured to let the inert gas flow from an inside to an outside of the main body, the flow portion being made of porous ceramic;
• and
• an insulating adhesive configured to fix the buried member to the main body,
• wherein a ratio of a diameter of an outer circumference of the buried portion to a diameter of a circular region enclosing all of the through holes is 1.2 or higher,
• the pores of the porous ceramic are configured to allow the inert gas flow from the inside to the outside of the main body, and
• the flow portion has an exposed surface on an outside surface of the main body.