The BiPo-3 detector is running in Canfranc Underground Laboratory (LSC, Spain) since 2013. It is a new generation detector, dedicated to measure ultra high natural radiopurity in Tl-208 and Bi-214 of thin materials, with a total surface area of measurement of 3.6 m2. The Tl-208 and Bi-214 isotopes are the two main background natural isotopes in the search for the neutrinoless double decay. The BiPo-3 detector has been initialy developped to measure the radiopurity of the selenium double $\beta$ source foils of the SuperNEMO experiment. It is today a generic detector which measures with an unprecedented sensitivity, materials of other double beta experiments. For the LRT workshop, we will present the experimental design and performances of the detector and the main results of the first measurements. An ultra low level of background has been measured in Tl-208 and Bi-214: after several months of background measurement, surface activities of the scintillators of A(Tl)= 1.0 \pm 0.2 microBq/m2 and A(Bi-214)= 1.8 \pm 0.4 microBq/m2 are measured. Given these levels of background, the BiPo-3 detector is able to qualify the radiopurity of a SuperNEMO selenium foil with a sensitivity of about 3 microBq/kg in Tl-208 and 30 microBq/kg in Bi-214 (90\% C.L.) with a six month measurement. The detection efficiency and the Monte-Carlo simulations of the BiPo-3 detector have been validated by measuring a calibrated aluminium foil. First samples of various double beta experiments (mostly SuperNEMO but also CUORE, Lumineu and Zaragoza low radioactive TPC) have been measured with the BiPo-3 detector. The first SuperNEMO enriched selenium foils are under measurement and the preliminary results of this measurment will been presented.