Heat radiation plate and submarine apparatus

摘要

A heat radiation plate includes a depressed portion into which thermally-conductive resin that transfers heat of an electronic component to the heat radiation plate is poured, and a plurality of check portions configured to be provided to the depressed portion and with an upper surface portion and a lower surface portion stepwise at positions lower than an outer edge portion of the depressed portion and higher than a bottom surface portion of the depressed portion so that a liquid level of the thermally-conductive resin is visually checkable, wherein when the thermally-conductive resin is normally filled in the depressed portion, each of the lower surface portions of the plurality of check portions is covered with the thermally-conductive resin and each of the upper surface portions of the plurality of check portions is exposed without being covered with the thermally-conductive resin.