An expansion valve 101 comprises a substantially prismatic-shaped valve body 301 made of aluminum alloy. On the valve body 301 is formed a first passage 32 through which a liquid-phase refrigerant travels towards an evaporator, and a second passage 34 through which a gas-phase refrigerant travels from the evaporator toward a compressor. On the upper portion of the valve body 301 is mounted a power element portion 36 for driving the valve mounted in the middle of a first passage 32. On the side surfaces 301a of the valve body 301 are formed protruding portions 301c, and to the protruding portions, penetrating holes 50 for inserting the bolt for mounting the expansion valve are formed.