The seat slide apparatus

The present invention provides a seat slide device. In the engaging member (20) upward guide (40) when assembled, the second rotary shaft portion (26L) inserted into the shaft receiving hole (47) of the first side wall portion (44a) from inside the upper rail (40). After the insertion, the second rotational shaft to the portion (26L) is inserted into the shaft portion of the second side wall (44b) of the receiving hole 47, rotation of the locking member (20). At this time, to allow the shaft-side length (L2) set to the maximum rotation length (L4) is larger than the shaft side, thereby inhibiting the shaft receiving hole (47) of the second rotary shaft portion (26L) and the second side wall portion (44b) of an edge portion contacting the rotation shaft of prejudice to the insertion portion (26).