An electronic component mounting device comprising: an electronic component insertion device that is configured to insert an electronic component into a board from one side of the board within a component mountable region that is set in advance; and a viscous fluid applying device that is configured to apply molten solder as a viscous fluid to the board from the other side of the board, wherein the viscous fluid applying device includes at least one flow tank that is configured to accommodate the viscous fluid and to eject the viscous fluid, the electronic component mounting device being characterized in that the viscous fluid applying device is configured to apply the viscous fluid in parallel with insertion of the electronic component into the board by the electronic component insertion device, the viscous fluid applying device further includes a flowtank moving device that is configured to move each of the at least one flow tanks to not only the component mountable region, but also a region outside the component mountable region, wherein the region outside the component mountable region includes a maintenance region in which at least one maintenance operation can be performed on at least one of the flow tanks (206, 206R), wherein the electronic component mounting device includes a maintenance device that is configured to perform maintenance of the flowtank (206, 206R) which is an object of maintenance from the least one flowtank (206, 206R), and wherein the maintenance device includes (a) an inspection unit that is configured to perform inspection of the flow tank (206, 206R) that is the object of maintenance and (b) an inspection unit moving device that is able to move the inspection unit between the standby position and an inspection position at which inspection of the flow tank (206, 206R), which is in the maintenance region and is the object of maintenance, is able to be performed. an electronic component insertion device that is configured to insert an electronic component into a board from one side of the board within a component mountable region that is set in advance; and a viscous fluid applying device that is configured to apply molten solder as a viscous fluid to the board from the other side of the board, wherein the viscous fluid applying device includes at least one flow tank that is configured to accommodate the viscous fluid and to eject the viscous fluid, the electronic component mounting device being characterized in that the viscous fluid applying device is configured to apply the viscous fluid in parallel with insertion of the electronic component into the board by the electronic component insertion device, the viscous fluid applying device further includes a flowtank moving device that is configured to move each of the at least one flow tanks to not only the component mountable region, but also a region outside the component mountable region, wherein the region outside the component mountable region includes a maintenance region in which at least one maintenance operation can be performed on at least one of the flow tanks (206, 206R), wherein the electronic component mounting device includes a maintenance device that is configured to perform maintenance of the flowtank (206, 206R) which is an object of maintenance from the least one flowtank (206, 206R), and wherein the maintenance device includes (a) an inspection unit that is configured to perform inspection of the flow tank (206, 206R) that is the object of maintenance and (b) an inspection unit moving device that is able to move the inspection unit between the standby position and an inspection position at which inspection of the flow tank (206, 206R), which is in the maintenance region and is the object of maintenance, is able to be performed.