A vehicle for cleaning collector mirrors in solar thermal energy installations, includes an operating cab (2), a body (3) for housing and holding the different items, a rolling system for moving the vehicle, a clean water tank, an assembly for discharging the clean water, at least one structure for spraying clean water (100)) onto the surfaces of the mirrors (22) and a tray (46) for collecting the water used in cleaning the mirrors; a set of lifting columns (5, 6); and supports (53, 63) for the cleaning and/or drying assemblies able to slide along the lifting columns, and in which the cleaning assembly includes a structure fitted with a rigid bar (91), which assumes the profile of the mirror to be cleaned, the bar being provided with an external rotation assembly for a brush.