An image forming apparatus comprising: a housing accommodating an image forming unit therein and having an opening at one side surface thereof; a cover member pivotally supported to a lower edge portion of the opening and rotated to an outer side of the housing from a closed state, in which the opening is closed, by employing a shaft as a fulcrum, thereby opening the opening; and a long belt-shaped support member having one end portion mounted at the housing and the other end portion mounted at the cover member, and restricting an opening angle of the cover member to a predetermined maximum opening angle, characterized in that the support member is provided at an intermediate portion thereof in a longitudinal direction with wavelike portions having a wave shape when viewed from a width direction perpendicular to the longitudinal direction and having elasticity in the longitudinal direction, the support member is folded in a U shape when viewed form the width direction of the support member when the cover member is in a closed state and is accommodated in the housing, a flat portion having a straight line shape when viewed from the width direction of the support member is formed at a part of the support member, to which bending stress is applied at the time of opening and closing of the cover member,- the wavelike portions are respectively formed at both sides of the flat portion in the longitudinal direction of the support member, when the cover member is in the closed state, only the flat portion of the support member is curved in a U shape and the wavelike portions of the support member which are not curved are accommodated in the housing, in a case in which a radial direction inside and a radial direction outside of the support member when the flat portion has been curved in a U shape are respectively employed as a curved inside and a curved outside, each wavelike portion has a shape in which a plurality of mountain shaped convex portions becoming convex at the curved inside are connected to one another when viewed from the width direction of the support member, and each convex portion comprises a base and an apex, wherein both end portions of the flat portion in the longitudinal direction are respectively connected to the bases of the convex portions adjacent to the flat portion, so that when the cover member has entered the closed state, the flat portion is curved in a predetermined direction so as to be able to be accommodated in the housing. a housing accommodating an image forming unit therein and having an opening at one side surface thereof; a cover member pivotally supported to a lower edge portion of the opening and rotated to an outer side of the housing from a closed state, in which the opening is closed, by employing a shaft as a fulcrum, thereby opening the opening; and a long belt-shaped support member having one end portion mounted at the housing and the other end portion mounted at the cover member, and restricting an opening angle of the cover member to a predetermined maximum opening angle, characterized in that the support member is provided at an intermediate portion thereof in a longitudinal direction with wavelike portions having a wave shape when viewed from a width direction perpendicular to the longitudinal direction and having elasticity in the longitudinal direction, the support member is folded in a U shape when viewed form the width direction of the support member when the cover member is in a closed state and is accommodated in the housing, a flat portion having a straight line shape when viewed from the width direction of the support member is formed at a part of the support member, to which bending stress is applied at the time of opening and closing of the cover member,- the wavelike portions are respectively formed at both sides of the flat portion in the longitudinal direction of the support member, when the cover member is in the closed state, only the flat portion of the support member is curved in a U shape and the wavelike portions of the support member which are not curved are accommodated in the housing, in a case in which a radial direction inside and a radial direction outside of the support member when the flat portion has been curved in a U shape are respectively employed as a curved inside and a curved outside, each wavelike portion has a shape in which a plurality of mountain shaped convex portions becoming convex at the curved inside are connected to one another when viewed from the width direction of the support member, and each convex portion comprises a base and an apex, wherein both end portions of the flat portion in the longitudinal direction are respectively connected to the bases of the convex portions adjacent to the flat portion, so that when the cover member has entered the closed state, the flat portion is curved in a predetermined direction so as to be able to be accommodated in the housing.