A drawer unit including a housing and a drawer inserted into the housing in inserting direction and drawn therefrom in drawing direction is provided. A locking member is mounted on the housing or the drawer to extend in direction intersecting the inserting direction, and is rotatable on a rotating shaft extending in the inserting direction such that when the drawer is inserted, the locking member rotates from unlock position to lock position in locking direction while rotating from the lock position to the unlock position in unlocking direction prior to drawing of the drawer. A locking wall and a pushing wall are mounted on the other of the housing and the drawer. The locking member in the lock position is engaged with the locking wall. When being rotated in the unlocking direction, the locking member is contacted with the pushing wall, which pushes the drawer in the drawing direction.