To provide an inexpensive engaging device which enables easy and sure engagement or disengagement of opposedly set female and male resin strip fastener by arranging at least in two lines side by side.

An engaging device 1 is constituted of a body 2 of the engaging device and a pinch-press fitting member 3 of the body 2 of the engaging device. The body 2 of the engaging device comprises right and left stripe pieces 2a and 2a which are made doubly foldable at a base part 4 successively arranged and are provided with fitting grooves 5 and engagement recessed parts 7 in number corresponding to the number of stripes of the fasteners, and a stopper 6 protrusively provided short so as to be positioned before the fitting grooves 5 on the side of the successively arranged base part 4. In the pinch-press fitting member 3, engagement stripes 12 at the open end part side are engaged with the recessed parts 7 to pinch the body 2 of the engaging device from above and below thereby preventing the body 2 of the engaging device from being separated from the peripheral rim of an opening part of a sealed bag.