Abstract: A safety latch for supporting a post in a post driver while the post is being driven into the ground. A post-engaging roller is mounted on a lever arm that is pivotally attached to the post driver and moveable between a released position for positioning of a post in the post driver and a working position where the roller is in supporting engagement with the post. A spring biases the roller to maintain supporting engagement with the post while it is driven. In a preferred embodiment, the spring is part of an over-center device for biasing the safety latch to both the released and working positions depending on which side of center the lever arm is positioned.