A circuit board connecting device comprising a first connector which having a first fixing metallic member attached to a first housing, a second connector having a second fixing metallic member attached to a second housing, and holding means operative to prevent the second housing from being undesirably separated from the first housing under a condition in which the first and second housings are coupled with each other, wherein end portions of a resilient movable holding member provided on the first connector to be movable in a predetermined direction are supported respectively by the first fixing metallic member to engage respectively with portions of the second fixing metallic member for holding the second housing when the second housing is coupled with the first housing, so that the end portions of the resilient movable holding member and the portions of the second fixing metallic member constitute the holding means.