It could be Jedi Master Luminara Unduli's lightsaber.
This is a scan from The Visual Dictionary of Star Wars, Episode II - Attack of the Clones.
The caption states that her lightsaber follows a "common lightsaber design".
In fact, the same page shows Plo Koon's lightsaber, which is very similar:
The main difference is in the color of the "radiator casing", which is golden in Luminara Unduli's saber and silver/steel coloured in Plo Koon's; moreover, Plo Koon's lightsaber shows blue markings at the opposite end.
This image, a particular taken from the image gallery in her official databank page, shows her some years later, in the Clone Wars animated series, using the same lightsaber:
There is a non-matching detail: the color of the round buttons, which are green and grey in the question image and red and green in these images. However, this could be due to degradation of the paint on the prop, especially as the buttons would be right in the grip of the person holding the lightsaber.
Additional images showing the lightsaber (click to enlarge), found by our most excellent chancellor @Valorum: