A circuit board mounting support for supporting a first electronic circuit integration includes a bearing member. The first electronic circuit integration includes a circuit board, an electronic component engaged with a first surface of the circuit board, and multiple legs for engaging with the bearing member. The circuit board has a mounting area for mounting the electronic component and a second surface opposite to the first surface. The bearing member includes a groove and an engaging portion connected to a peripheral edge of the groove. A corresponding area is defined on the bearing member and corresponds to the mounting area of the circuit board. When the bearing member is engaged with the circuit board, an opening of the groove and the engaging portion face the second surface. A junction that each of the legs is engaged with the bearing member is located out of the corresponding area.