An operation support device includes a connecting body in which a first support body and a second support body are detachably connected to each other a first shaft engaging section a shaft connecting member having a connection engaging section engaged with the first shaft engaging section and a shaft fixing member. The shaft fixing member is movably installed with respect to a first shaft section or a second shaft section and is configured to selectively form a shaft engagement fixing state in which the connection engaging section is held down to retain an engagement state such that the connection engaging section is engaged with the first shaft engaging section and a second state in which holding down to the connection engaging section is released in accordance with a moved position with a moved position of the shaft fixing member.
