Heat exchanger and heat pump device

A heat exchanger comprising:

• a gas-refrigerant pipe;
• a header connected to the gas-refrigerant pipe;
• and
• heat transfer tubes connected to the header,
• wherein the header includes:
• a first plate member;
• and
• a second plate member that is stacked on the first plate member in a plate-thickness direction,
• wherein the first plate member includes a first opening that constitutes an internal space of the header,
• wherein the second plate member includes a second opening that, together with the first opening, constitutes the internal space of the header,
• wherein the internal space of the header communicates with the heat transfer tubes,
• wherein a first direction is perpendicular to both the plate-thickness direction and a direction in which the heat transfer tubes are arranged,
• wherein a width of a part of the first opening in the first direction is different from a width of the second opening in the first direction,
• wherein the heat transfer tubes connect to the header at connection portions,
• wherein, when viewed in the plate-thickness direction, an overlapping region of the first opening and the second opening overlaps a cross section of connection portions of two or more of the heat transfer tubes,
• wherein the second plate member is disposed at a position that is closer to the connection portions than the first plate member,
• wherein a width of a part of the second opening in the first direction is larger than the width of the first opening in the first direction, and
• wherein the first plate member includes, at a surface on a side at which the second plate member is stacked, a pressure-receiving surface that extends to an inner side of the width of the second opening in the first direction from an outer side of the width of the first opening in the first direction, and that faces the internal space of the header.