Medical device and method of manufacturing the same

A medical device comprising:

• a case obtained by mating a first case portion and a second case portion to each other, the case having a housing space inside;
• an elastic membrane as an elastic member attached to the case and with which a first housing space covered by the first case portion and a second housing space covered by the second case portion are separated from each other;
• fixing parts provided at respective peripheries of the first case portion and the second case portion and at which the first case portion and the second case portion that are mated to each other are fixed to each other by melting;
• holding surfaces provided at the respective peripheries of the first case portion and the second case portion and between which a peripheral edge of the elastic membrane is held;
• a sealing part provided at the periphery of the first case portion or the second case portion on an inner side with respect to the fixing parts and that seals an entirety of the peripheral edge of the elastic membrane held between the holding surfaces and
• a releasing part that releases a pressure in an air gap that is located between the case and the elastic membrane and extends between the sealing part and the fixing parts wherein the releasing part serves as a cut part provided in a region of the fixing part of the first case portion or the second case portion, and when the first case portion and the second case portion are fixed to each other at the fixing parts,
• wherein the cut part releases the pressure generated in the air gap and the cut part is closed by melting of the fixing parts or regions around the fixing parts;
• and
• wherein the fixing parts are annularly formed in the first case portion and the second case portion, and the cut part extends in a radial direction in the fixing parts of the first case portion and the second case portion.