A MEMS device includes a protective substrate on which is mounted a driving circuit that drives a piezoelectric actuator and on which is formed an interconnect pattern electrically connected to the driving circuit, and a sealing substrate that includes a first opening and that is bonded to the protective substrate using an adhesive so that part of the interconnect pattern is located between the protective substrate and the sealing substrate. The interconnect pattern includes a connection portion that extends from a bonding region where the protective substrate and the sealing substrate are bonded by the adhesive to the first opening, and that has a connection region electrically connected to the driving circuit. A groove is formed in the connection portion between the connection region and a border between the bonding region and the connection portion.