An electrochemical reaction unit containing a single cell including an electrolyte layer containing solid oxide, and a cathode and an anode which face each other in a first direction with the electrolyte layer intervening therebetween; a current collector disposed on a cathode side of the single cell and having a protrusion protruding toward the cathode; an electrically conductive coat covering a surface of the current collector; and an electrically conductive bonding layer bonding the cathode and the protrusion covered with the coat. In at least one section of the protrusion taken in parallel with the first direction, the protrusion covered with the coat has a covered portion covered with the bonding layer and an exposed portion exposed from the bonding layer and including a corner portion of the protrusion covered with the coat.