To provide an open type disposable diaper which can be easily worn in a standing position.

The open type disposable diaper 20 includes a chassis 30 provided with a skin abutting surface 21, a clothing abutting surface 22, a length direction, a width direction, a first girth area 23 and a second girth area 25 arranged in the length direction, and a crotch area 24 positioned between the girth areas. The chassis 30 is provided with a fastening system 31 for connecting the first and second girth areas 23 and 25 on both side parts 26 of the width direction. The first girth area 23 is provided with a temporary fixing means 50 provided with a proximal end part 53 and a connection part 54 extended from there and capable of releasably holding the diaper 20 to clothing put on the upper half body of a diaper wearer. The temporary fixing means 50 is fixed to the clothing abutting surface 22 at the proximal end part 51 and is provided with a fastening element 52 connectable to the clothing on the connection part 54.