A tool changer 10 includes a tool change arm 40 having tool holding portions 42, 52 at ends thereof, a support shaft supporting the tool change arm 40, a rotation mechanism including a rotation drive motor 25 and rotating the tool change arm 40 about an axis of the support shaft, a forward/backward movement mechanism including a forward/backward movement drive motor 13 and moving the tool change arm 40 forward and backward along the support shaft, and a mount base 11 having the rotation drive motor 25, the forward/backward movement drive motor 13 and the support shaft mounted thereon. The tool changer has a restraining member 60 provided thereon which restrains movement of the tool change arm 40 in a direction along the support shaft by engaging with the tool change arm 40 positioned at an original position.