To suppress the tilting of a slider which is elevated under a state in which the force point side and the reaction force side are respectively supported by a rack pinion mechanism when a cap has sealed the nozzle-formed surface of a liquid jetting head.

This maintenance unit comprises the slider which is elevated under the state wherein one end side is cantilever-supported by a cylindrical cam, and the cap which is supported by the slider, and at the same time, can seal the nozzle formed surface of the recording head by the raising of the slider. On the slider, a rear side pinion 38a and a front side pinion 38b are provided in a manner to be integrally rotatable with each other by a rotating shaft 38. On the internal surface of the rack 39 (the right side wall of a unit case), a rear side tooth row 39a and a front side tooth row 39b which respectively engage with both pinions 38a and 38b are provided. Then, both tooth rows 39a and 39b are arranged while being positionally shifted from each other so that the corresponding teeth of the front side tooth row 39b may become higher than those of the rear side tooth row 39a between the tooth rows.