A stacking-type header, comprising: a first plate-shaped unit having a plurality of first outlet flow passages formed therein; and a second plate-shaped unit being mounted on the first plate-shaped unit and having a first inlet flow passage formed therein and a distribution flow passage formed therein, the distribution flow passage being configured to distribute refrigerant, which passes through the first inlet flow passage to flow into the second plate-shaped unit, to the plurality of first outlet flow passages to cause the refrigerant to flow out from the second plate-shaped unit, wherein the distribution flow passage comprises a branching flow passage comprising: an opening port; a first straight-line part parallel to a gravity direction, the first straight-line part having a lower end communicating with the opening port through a first connecting part; and a second straight-line part parallel to the gravity direction, the second straight-line part having an upper end communicating with the opening port through a second connecting part, wherein at least a part of the first connecting part and at least a part of the second connecting part are not being parallel to the gravity direction, and wherein the branching flow passage is configured to allow the refrigerant to flow thereinto through the opening port, pass through each of the first connecting part and the second connecting part to flow into each of the lower end of the first straight-line part and the upper end of the second straight-line part, and flow out from the branching flow passage through each of an upper end of the first straight-line part and a lower end of the second straight-line part, characterised in that a straight line connecting between an upper end of the first straight-line part and a lower end of the second straight-line part is being parallel to a longitudinal direction of the second plate-shaped unit. a first plate-shaped unit having a plurality of first outlet flow passages formed therein; and a second plate-shaped unit being mounted on the first plate-shaped unit and having a first inlet flow passage formed therein and a distribution flow passage formed therein, the distribution flow passage being configured to distribute refrigerant, which passes through the first inlet flow passage to flow into the second plate-shaped unit, to the plurality of first outlet flow passages to cause the refrigerant to flow out from the second plate-shaped unit, wherein the distribution flow passage comprises a branching flow passage comprising: an opening port; a first straight-line part parallel to a gravity direction, the first straight-line part having a lower end communicating with the opening port through a first connecting part; and a second straight-line part parallel to the gravity direction, the second straight-line part having an upper end communicating with the opening port through a second connecting part, an opening port; a first straight-line part parallel to a gravity direction, the first straight-line part having a lower end communicating with the opening port through a first connecting part; and a second straight-line part parallel to the gravity direction, the second straight-line part having an upper end communicating with the opening port through a second connecting part, wherein at least a part of the first connecting part and at least a part of the second connecting part are not being parallel to the gravity direction, and wherein the branching flow passage is configured to allow the refrigerant to flow thereinto through the opening port, pass through each of the first connecting part and the second connecting part to flow into each of the lower end of the first straight-line part and the upper end of the second straight-line part, and flow out from the branching flow passage through each of an upper end of the first straight-line part and a lower end of the second straight-line part, characterised in that a straight line connecting between an upper end of the first straight-line part and a lower end of the second straight-line part is being parallel to a longitudinal direction of the second plate-shaped unit.