A mechanical pencil comprising a cartridge slidably inserted into the lower part of a barrel and containing a piece of pencil lead; a needle member for normally restricting the upward movement of said pencil lead; and a chuck for causing said cartridge to project from the lower end of the barrel upon depression of a push button mounted at the upper end of the barrel and for normally holding said needle member in position, whereby said cartridge and pencil lead may be jointly replaced when the latter is fully consumed.