A package for housing an electronic component comprising: a substrate comprising an upper surface including a mount region adapted for mounting an electronic component; a frame body disposed on the upper surface of the substrate surrounding the mount region, and comprising a through-hole portion which opens to an inside and outside of the frame body; and an input/output member disposed on the frame body so as to block the through-hole portion and comprising: a second insulating layer stacked on a first insulating layer, the second insulating layer protruding beyond the first insulating layer on the outside of the frame body; a plurality of wiring conductors which are adapted to be electrically connected to the electronic component, the wiring conductors extending to the inside and outside of the frame body and also extending along a lower surface of the second insulating layer on the outside of the frame body; characterized by: a cutout portion which is cut out in the lower surface of the second insulating layer and extends along a gap between adjacent ones of the plurality of wiring conductors on the lower surface along the wiring conductors to an outer side surface of the input/output member, and a side surface of the first insulating layer being provided with a recess portion which is disposed directly below the cutout portion. a substrate comprising an upper surface including a mount region adapted for mounting an electronic component; a frame body disposed on the upper surface of the substrate surrounding the mount region, and comprising a through-hole portion which opens to an inside and outside of the frame body; and an input/output member disposed on the frame body so as to block the through-hole portion and comprising: a second insulating layer stacked on a first insulating layer, the second insulating layer protruding beyond the first insulating layer on the outside of the frame body; a plurality of wiring conductors which are adapted to be electrically connected to the electronic component, the wiring conductors extending to the inside and outside of the frame body and also extending along a lower surface of the second insulating layer on the outside of the frame body; characterized by: a cutout portion which is cut out in the lower surface of the second insulating layer and extends along a gap between adjacent ones of the plurality of wiring conductors on the lower surface along the wiring conductors to an outer side surface of the input/output member, and a side surface of the first insulating layer being provided with a recess portion which is disposed directly below the cutout portion. a second insulating layer stacked on a first insulating layer, the second insulating layer protruding beyond the first insulating layer on the outside of the frame body; a plurality of wiring conductors which are adapted to be electrically connected to the electronic component, the wiring conductors extending to the inside and outside of the frame body and also extending along a lower surface of the second insulating layer on the outside of the frame body; characterized by: a cutout portion which is cut out in the lower surface of the second insulating layer and extends along a gap between adjacent ones of the plurality of wiring conductors on the lower surface along the wiring conductors to an outer side surface of the input/output member, and a side surface of the first insulating layer being provided with a recess portion which is disposed directly below the cutout portion. a cutout portion which is cut out in the lower surface of the second insulating layer and extends along a gap between adjacent ones of the plurality of wiring conductors on the lower surface along the wiring conductors to an outer side surface of the input/output member, and a side surface of the first insulating layer being provided with a recess portion which is disposed directly below the cutout portion.