Abstract: A miniature peristaltic pump includes a rotor with three turning rollers, a support piece with a rounded portion arranged substantially concentric to the rotor and against which, when operating, the rollers are brought to compress a flexible tubing connected to a reservoir of solution to push it outwards and for automatically compensating positional deviations between the roller and the support piece. Each roller has a substantially cylindrical body and a shaft on which the body is rotatably mounted. The ends of the roller shafts are located in oblong slots radially recessed in the rotor. The compensating device includes two springs arranged at the respective ends of the shafts and have a central port concentric to the rotor and three curved spring arms, one for each roller, with one end connected to the central part and the other end bearing on the corresponding end of a roller shaft to push it outwards and thus enable it to exert a substantially constant force of pressure.