A nail magazine for alternatively accommodating T-nails or U-nails includes a nail track and a stop block. The nailing track has a bottom notch and a first nail hole upwardly extended from the bottom notch for holding a T-nail. The stop block is positioned in the bottom notch of the nailing track and has a top side, a left side and a right side, which define with a peripheral wall of the bottom notch of the nailing track a second nail hole for holding a U-nail. The stop block further has a top cut groove aligned with the first nail hole such that the T-nail held in the first nail hole is in coincidence with an axis of a driving path that aligns with the second nail hole, thereby enabling the T-nail to be positively and straightly driven into a workpiece.