A low profile module is provided that has a high functionality achieved by increasing the component mounting density. In spite of achieving high functionality in a module 100 by respectively mounting components such as a semiconductor substrate 104 and chip components 105 on the two main surfaces 101a and 101b of a wiring substrate 101, the low-profile module 100 can be provided which has a high functionality as a result of increasing its component mounting density by forming a thickness Ha of a first component layer 102 formed by mounting only the semiconductor substrate 104 face down on one main surface 101a of the wiring substrate 101 so as to be smaller than the thickness of a second component layer 103 formed by mounting a plurality of chip components 105 on the other main surface 101b of the wiring substrate 101.