To improve mechanical connection strength between an MEMS chip and a wiring board in an MEMS device adopting ACF packaging.

In an MEMS device, an anisotropic conductive film (ACF) 30 is sandwiched by an MEMS chip 10 and a flexible printed circuit board 20 to be crimped thereby mechanically and electrically connecting the MEMS chip 10 with the flexible printed circuit board 20. Multiple recessed shapes 19 are provided at a crimp region on the MEMS chip 10 which is crimped to the ACF 30. When the MEMS chip 10 and the flexible printed circuit board 20 are crimped by the ACF 30, the ACF 30 partially penetrates into the recessed shapes 19 on the MEMS chip 10 thereby improving the mechanical connection strength between the MEMS chip 10 and the flexible printed circuit board 20.