To provide a lift mechanism capable of attach work of a bolt to a bracket smoothly and appropriately.

The lift mechanism includes: a bracket XB which has a bolt insertion hole XB1a for allowing a screw part XA1 of a bolt XA and a flange part XA3 to insert and can hold the bolt XA rotatably; a stay XC having an internal thread XC31 with which the screw part XA1 of the bolt XA can be threadedly engaged; a first insertion hole XD11 which is placed in a gap formed between an operation part XA2 of the bolt XA and the flange part XA3 and allows the screw part XA1 and the flange part XA3 to insert; and a second insertion hole XD12 which allows only the screw part XA1 to insert. The mechanism also includes: a coming-off prevention member XD movable between a first connection position Y allowing the first insertion hole XD11 to connect with the bolt insertion hole XB1a and a second connection position Z allowing the second insertion hole XD12 to connect with the bolt insertion hole XB1a; and a cap XE for regulating that the coming-off prevention XD positioned at the second connection position Z moves to the first connection position Y.