A cell monitor connector is provided that can prevent detachment of the cell monitor connector from a fuel cell device with a simple configuration. A connector 4 for measuring voltage has a housing 41 with a plurality of slits 45 formed therein and an end of a separator 21 of a plurality of fuel cells 2 can be inserted into the slits 45. The housing 41 has a rib 46R at at least one end in the stacking direction of the fuel cells 2 such that the rib 46R projects in a direction perpendicular to the stacking direction.