You Do Need power plug adapter while traveling from Thailand to Niger.

Here is Why You Need An Adapter

The outlet and plug type used in Niger are C, D, E and F and in Thailand are A, B, C and O. This is how they look like.

Thailand

In Thailand, outlets of type A, B, C and O are in use.

Type A

Type B

Type C

Type O

Niger

In Niger, outlets of type C, D, E and F are in use.

Type C

Type D

Type E

Type F