To provide a fluid pressure cylinder having a stroke sensor, which enables the utilization of a scale rod possibly employing a more inexpensive magnetic sensor and that used as piston with the shortening of the distance between recessed parts and the magnetic sensor and the distance between protruded parts and the magnetic sensor, by eliminating the denting of a part corresponding to the recessed parts of a cylinder body under an extraneous force or an internal pressure of the cylinder body, even if a cylinder body for a thin cover is used.

There are a constituted a columnar body comprising a magnetic material, a scale in which protruded parts and recessed parts are formed in plurality alternately in the axial direction thereof on the external surface of the columnar body and a cylinder body, comprising a non magnetic covering the outer circumference of the columnar body. A magnetic sensor reads out changed in magnetism between the magnetic sensor 3 and the protruded parts, and between the magnetic sensor and the recessed parts, when the columnar body moves in the axial direction thereof to detect movement value of the columnar body converting the changes in magnetism to a voltage or a current. In a scale rod of this type, the inner circumference part of the cylinder body is pressed onto the respective surfaces of the protruded parts by plastic working of the cylinder body, while being dug into the whole or a part of the insides of the recessed parts.