A server casing using a sliding apparatus for blade servers includes a chassis and the sliding apparatus. The chassis includes a blocking member. The sliding apparatus includes a first fastening plate, a second parallel fastening plate mounted to the first fastening plate, and a sliding plate configured to be slidably connected to the second fastening plate. The sliding plate is received between the first fastening plate and the second fastening plate and a locking member includes a first end and a second end. The first end is rotatably connected to the second fastening plate and includes a locking portion, the second end is connected to the sliding plate. The locking portion can move between a locking position, where the locking member is locked by the blocking member, and an unlocking position, where the locking member is unlocked by the blocking member.