An oscillator includes a substrate having a first substrate main surface and a substrate side surface, and a lid body bonded to the substrate and including a metal material, in which the substrate includes a substrate body having a first substrate body main surface corresponding to the first substrate main surface and a substrate body side surface corresponding to the substrate side surface, and provided with a cutout portion in the substrate body side surface, a side surface wiring provided along the cutout portion, a filling member provided in the cutout portion, and an insulating coating member provided on the first substrate body main surface.