Heat exchanger and outdoor unit comprising said heat exchanger

A heat exchanger comprising:

• an inlet header located on a refrigerant inlet side;
• an outlet header located on a refrigerant outlet side;
• a plurality of rooms partitioned by partition plates and provided inside one header of the inlet header or the outlet header;
• a plurality of flat tubes connected in parallel between each room of the plurality of rooms provided in the one header of the inlet header or the outlet header and the other header of the inlet header or the outlet header;
• a distributor provided in a refrigerant pipe;
• a plurality of branch pipes connected to each room and the distributor,
• wherein the branch pipe has a branch portion provided between the room and the distributor depending on an air velocity distribution in the heat exchanger, and
• the number of the branch portions of the branch pipe connected to the room, to which the flat tubes located in a part having a high air velocity are connected, is less than the number of the branch portions of the branch pipe connected to the room, to which the flat tubes passing through a part having a low air velocity are connected.