A robot cleaner includes a 3D sensor unit installed on a main body to sense nearby objects and output sensing information; a secondary sensor unit configured to sense nearby objects and output sensing information; a storage unit configured to set a diagnostic algorithm according to a diagnostic mode in advance; an input unit configured to input an execution command for the diagnostic mode; a control unit configured to auto-correct the diagnostic mode for the 3D sensor and a parameter of the 3D sensor unit using the diagnostic algorithm in response to the execution command; and an output unit configured to output an execution result of the diagnostic mode and a correction message.