Cushioning member and method for manufacturing cushioning member

A cushioning member composed of at least one resin sheet fused in a form of a bag, comprising:

• an accommodating bag portion that accommodates a medium;
• a first fusing portion that defines a perimeter of the accommodating bag portion wherein, at an end portion of the accommodating bag portion, the first fusing portion is bent inward toward a center portion of the accommodating bag portion such that an opening is defined that allows the medium to pass therethrough;
• a check valve having a first end and a second end and provided at the opening such that the first end is located inside the accommodating bag portion and the second end is located outside the accommodating bag portion;
• the medium accommodated in the accommodating bag portion;
• a second fusing portion (i) that is immediately adjacent to the first fusing portion on end sides of the check valve that are opposite in a direction intersecting a direction in which the check valve protrudes from the accommodating bag portion, and (ii) defines a channel that communicates with the opening;
• and
• a third fusing portion that is connected to the second fusing portion and seals the channel, the third fusing portion being provided across and abuts against a portion of the check valve that protrudes from the accommodating bag portion.