You Do Need power plug adapter while traveling from Myanmar (Burma) to Guinea-Bissau.

Here is Why You Need An Adapter

The outlet and plug type used in Guinea-Bissau is C and in Myanmar (Burma) are A, C, D, G and I. This is how they look like.

Myanmar (Burma)

In Myanmar (Burma), outlets of type A, C, D, G and I are in use.

Type A

Type C

Type D

Type G

Type I

Guinea-Bissau

In Guinea-Bissau, outlets of type C are in use.

Type C