A transformer includes: a bobbin on which a coil is wound; a core coupled with the bobbin to provide a magnetic flux, at least a portion of the core being installed on the PCB in a penetrating manner; and a base plate electrically connected to the coil and having a lead frame connected to the PCB, wherein the base plate is installed to be reversedly disposed at an upper side of the bobbin on the PCB, a space is formed between a lower surface of the base plate and an upper surface of the PCB, and the space between the lower surface of the base plate and the upper surface of the PCB is supported by a support member in contact with the upper surface of the PCB.