Organic interposer and method for manufacturing organic interposer

Provided are: an organic interposer enabling to improve insulation reliability; and a method for manufacturing the organic interposer. An organic interposer 10 is provided with an organic insulating laminated body 12 configured by including a plurality of organic insulating layers, and a plurality of wiring lines 13 arrayed in the organic insulating laminated body 12, and the wiring lines 13 and the organic insulating layers are partitioned from each other by barrier metal films 14. The organic insulating laminated body 12 may include: a first organic insulating layer 21 having a plurality of groove sections 21a in which the wiring lines 13 are disposed; and a second organic insulating layer 22 that is laminated to the first organic insulating layer 21 so that the wiring lines 13 are embedded.