A construction of the interior of an arm rest housing is provided. The cloth which forms the upper wall of a recessed arm rest housing is stitched to cloths forming a left and right side walls thereof keeping the seams outside. The extension of the cloth is extended around the frame located inside the seat and terminates in one end. This end is fixed to a fixing wire and a panel is affixed on the fixing wire. In this construction an improved interior construction of the arm rest housing in a seat for vehicles is disclosed wherein there is defined spaced in a portion of frame corresponding to the seams of the cloths, whereby the seams extend through such space into the inside of the seat. In this manner, bulging at the corners of the interior of the housing is avoided and the exterior appearance is enhanced.