A resonance device includes a first substrate formed of a semiconductor material or a glass material and having a recess which has an opening in a first main surface, a second substrate bonded to the first main surface and configured to close the opening of the recess, and a resonator element housed in the recess. An inner surface of the recess includes a side surface, a bottom surface, and a connection surface connecting the side surface and the bottom surface, the connection surface is a curved surface, and L1