A cylinder apparatus is provided with a stopper mechanism that operates when a piston rod extends and moves toward an upper end portion in an inner cylinder. This stopper mechanism includes a second cylinder provided movably relative to the piston rod and including a bottom portion on an upper end side in the inner cylinder and a cylinder portion extending from the bottom portion toward a lower end side, and a second piston provided so as to be able to move along with a movement of the piston rod to be fitted to the second cylinder. While being configured in this manner, the cylinder apparatus is configured in such a manner that a spring member 21 is provided between the second cylinder and a rod guide.