A laminated fluid warmer includes: a laminate including a target fluid layer having a plurality of target fluid channels through which a warming target fluid flows, and a warming fluid layer that is laminated on the target fluid layer and has a plurality of warming fluid channels through which a warming fluid for warming the target fluid layer flows; and a collection device that collects at least a part of the warming fluid accumulated in the plurality of warming fluid channels. The collection device includes a storage portion that receives the warming fluid flowing out from the warming fluid channel when collecting the warming fluid.