In a high frequency transformer, when a current flows between input-output ports, a magnetic flux produced by first and third coil conductor patterns of a primary coil is interlinked with a second coil conductor pattern of a secondary coil. A magnetic flux produced by the second coil conductor pattern of the primary coil is interlinked with the first and third coil conductor patterns of the secondary coil. The coil conductor patterns are wound so that when a current flows through a transformer, the directions of magnetic fields occurring within the first and third coil conductor patterns of the primary coil and the second coil conductor pattern of the secondary coil are the same and the directions of magnetic fields occurring within the first and third coil conductor patterns of the secondary coil and the second coil conductor pattern of the primary coil are the same.