A vacuum cleaner, which is a portable vacuum cleaner, including a tank body, a head portion disposed above the tank body, and a battery connection portion that is disposed at the head portion and is capable of connecting to a battery. A part of an upper end portion of the tank body has a bent shape or a curved shape, and the rest part of the upper end portion of the tank body has a shape neither bending inward nor curved inward. The vacuum cleaner may further include a battery connection portion disposed at the head portion and a brushless motor disposed at the head portion. The vacuum cleaner is easy to assemble, portable, convenient in checking the battery level, waterproof and has a good performance of drainage, high efficiency in dust vacuuming, small size and compact structure, light weight, and improved service period.