You Do Need power plug adapter while traveling from Poland 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 Poland are C and E. This is how they look like.

Poland

In Poland, outlets of type C and E are in use.

Type C

Type E

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