Searches for new particles and new phenomena with the ATLAS detector

Extensions of the Standard Model (SM) predict the existence of various new particles that have unique coupling to the SM particles. The signature of the new particles can some time be very different from the SM events. That would be the case for weakly-interacting long-lived particles decaying to collimated lepton-jets far away from the interaction point, or for production of highly-ionizing magnetic monopoles. The talk will review searches for new particles such as excited leptons or long-lived particles using data recorded by the ATLAS experiment at the LHC.