PLATE WITH FLOW PASSAGE

A plate with a flow channel according to the present invention includes: a main body portion in which a flow channel to let inert gas flow is formed; and a cover that covers a surface of the main body portion in which surface the flow channel is formed, wherein a buried member buried in an opening of the flow channel is provided in the flow channel of the main body portion, the buried member includes a buried portion fixed to the flow channel, and a flow portion that is held by the buried portion and that lets the inert gas flow from the inside to the outside of the main body portion, a plurality of through holes is provided in the flow portion, the buried member and the flow channel are fixed to each other by an insulating adhesive, and a ratio of a diameter of an outer circumference of the buried portion to a diameter of a smallest circle among circles including all the through holes is 1.2 or higher.