A damper includes a cylinder, an annular rod guide, a rod, an annular oil seal, and an annular seal holder. The cylinder internally forms an action chamber. The rod guide is secured to one side opening of the cylinder. The rod is inserted through an inner peripheral side of the rod guide so as to be axially movable. The oil seal is installed to the action chamber side of the rod guide to be slidably in contact with an outer peripheral surface of the rod. The seal holder supports the oil seal from the action chamber side. The rod guide includes a holding portion to hold the seal holder.