To increase the degree of freedom in the fixing position of a connecting block for expansion valve by making a first connection hole in the tank of a desired tube element, forming the tank of other tube elements larger than other tanks and making a second connection hole in the larger tank.

The multilayer heat exchanger 1 has a structure where tube elements 2 added with two other tube elements 2a, 2a and fins 3 are placed alternately in layers. Tank groups of pair tanks 4, 5 are juxtaposed above. A first connection hole is made in the tank 4a of one tube element 2a and interconnected with the outlet hole of a connecting block 20 for fixing an expansion valve. A large tank 4b elongated outward is formed in the other tube element 2a and a second connection hole made in the tank 4b is connected through a connection pipe with an inlet hole made in the connecting block 20.