PROBLEM TO BE SOLVED: To provide a conversion system, a conversion adapter, and an ultrasonic observation device capable of suppressing the protrusion of an adapter from the ultrasonic observation device and suppressing a decrease in an arrangement area of internal members in the ultrasonic observation device. thing. A conversion system according to the present invention has an ultrasonic observation apparatus provided on a surface that is connected to a conversion adapter, and has a housing portion that houses the conversion adapter and a device-side connector that is connected to the conversion adapter. Then, the conversion adapter mounts the first connector connected to the device-side connector, the second connector connected to the ultrasonic probe, and the first connector on one surface, and the other positioned on the opposite side of the one surface. A surface on which the second connector is mounted, and in the board, the first connector and the second connector are arranged at positions where the centers of the respective connectors are different from each other when viewed in the direction orthogonal to the one surface. .. [Selection diagram] Figure 2【課題】アダプタの超音波観測装置からの突出を抑制し、かつ超音波観測装置における内部部材の配設領域の減少を抑制することができる変換システム、変換アダプタ、および超音波観測装置を提供すること。【解決手段】本発明に係る変換システムは、超音波観測装置が、変換アダプタと接続する表面に設けられ、該変換アダプタを収容する収容部と、変換アダプタと接続する装置側コネクタと、を有し、変換アダプタが、装置側コネクタと接続する第１コネクタと、超音波プローブと接続する第２コネクタと、一方の面に第１コネクタを実装するとともに、一方の面の反対側に位置する他方の面に第２コネクタを実装する基板と、を有し、基板において、第１コネクタと第２コネクタとは、一方の面と直交する方向からみて、各コネクタ中心が互いに異なる位置に配置される。【選択図】図２
