[PROBLEMS] To provide a multi-function type oscillation actuator and a mobile terminal device capable of lowering the lowest acoustic resonance frequency and preventing a cut-off of a coil lead as well as improving acoustic characteristics and preventing sound leak. [MEANS FOR SOLVING PROBLEMS] A portion near to the outer circumference of a diaphragm (3) is bent to form a rising portion (3b) extending along an inner circumference (1a) of a housing (1) toward its open end. This rising portion (3b) serves as a corrugation to lower the lowest resonance frequency and the amplitude on the rising portion (3b) as a fulcrum is not large unlike the corrugation. Accordingly, the coil lead of a voice coil (4) is not broken easily. Furthermore, an extending portion (3c) is formed to extend along a flat surface (1b) formed at the open end of the housing (1) from the rising portion (3b) toward outside. This enlarges the entire radius of the diaphragm and improves the acoustic characteristic. Moreover, by arranging the flat surface (1b) of the housing (1) parallel to the extending portion (3c) of the diaphragm (3), a gasket or the like can easily be attached.