An opening and closing assembly includes a first casing, a second casing pivotally coupled to the first casing, and a support stand configured to support the second casing. The support stand includes a proximal end portion pivotally connected to one of the first and second casings, and a distal end portion slidably connected to the other thereof. The other of the first and second casings includes a guide portion for guiding the distal end portion, and first and second wall portions. The distal end portion includes a gripped portion gripped between the first and second wall portions, the gripped portion has a cross section having a width which increases, from one end of the cross section, to a maximum width and decreases from the maximum width until the other end of the cross section. The maximum width causes the first and second wall portions to be spaced apart.