A SAW chip (11) where ones are balanced signal terminals and the others are unbalanced signal terminals is mounted on a mounting board (12) in a flip chip manner, and the mounting board (12) and a surface of the SAW chip are covered with resin (19). At that time, grounds of first and second SAW filters (1, 2) in the SAW chip (11) are connected together and an annular pattern (14) is formed so as to surround a signal pattern of the SAW chip (11) on the mounting board (12) on which the SAW chip (11) is mounted, and the annular electrode (14) is connected to a ground pattern.