A sheet storage cassette of the present disclosure includes a sheet storage portion, a rack and a cursor. The cursor aligns sheets. The cursor includes a regulation portion which makes contact with the side ends of the sheets and a lock portion which includes at least one engagement protrusion that engages with the rack teeth of the rack. The at least one engagement protrusion each includes a second inclination surface which is inclined from a tip end portion toward a base portion in a second direction opposite to a first direction. At least one of the engagement protrusions includes a second vertical surface which is extended vertically downward from the base portion toward the tip end portion. At least one of the engagement protrusions includes a third inclination surface which is inclined in the second direction and which is extended to the tip end portion of the engagement protrusion.