A transformer includes: a multilayer board; one or more input conductive lines formed on the multilayer board, whose both ends connected to input terminals of a positive signal and a negative signal, respectively; one output conductive line formed adjacent to the one or more input conductive lines to form an electromagnetic coupling with the one or more input conductive lines, whose one end is connected to an output terminal and another end is connected to a ground; a power supply pad formed in an area of the one or more input conductive lines; and a harmonics remover formed between the one end and the another end of the output conductive line to remove harmonics components of a signal outputted from the output conductive line.