。
The compass needle always points north.
Literal
Compass [possessive-の] needle [topic-は] always north [object-を] indicates.
羅針盤 ('compass,' literally 'spiral-needle-board') is a traditional compound noun. 示す ('to indicate / show') takes を for what's being indicated. 常に ('always / constantly') is a formal adverb — more literary than いつも.