Abstract: A replacement lead case includes a case body that forms an inner space surrounded by a rear surface plate and right and left leg plates as a replacement lead accommodation room and has a lid body on the tip end thereof and a case part on a rear part thereof via a bendable thin part provided on the rear surface plate, and a cover member that has a U-shaped cross-section orthogonal to a longitudinal direction molded by a front surface plate and right and left outer leg plates covers the replacement lead accommodation room on a case body with the front surface plate and slidably supports the case body in the longitudinal direction with the leg plates positioned on the inside of the outer leg plates. A rail-shaped guide is formed on the lid body along the longitudinal direction, and the cover member includes a slider that contacts the guide.