You Do Need power plug adapter while traveling from Australia to Bangladesh.

Here is Why You Need An Adapter

The outlet and plug type used in Bangladesh are A, C, D, G and K and in Australia is I. This is how they look like.

Australia

In Australia, outlets of type I are in use.

Type I

Bangladesh

In Bangladesh, outlets of type A, C, D, G and K are in use.

Type A

Type C

Type D

Type G

Type K