A high-frequency connecting device includes a housing, a sandwiched member, an inner heat sink, a rear heat sink, a heat pipe, a upper heat sink and a connector. The inner heat sink is disposed inside the sandwiched member. The top and the bottom of the inner heat sink respectively have a first contact portion and a second contact portion. The upper heat sink has a third contact portion. A fourth contact portion is elastically disposed on the lower cover. The first and the second optical modules are respectively inserted into the upper and the lower spaces. The top and the bottom of the first optical module are in direct contact respectively with the third contact portion and the first contact portion, while the top and the bottom of the second optical module are in direct contact respectively with the second contact portion and the fourth contact portion.