A needle selecting apparatus for a weft knitting machine capable of performing a needle selecting position locking function without moving a selecting jack forward and backward is provided. In the needle selecting apparatus, as shown in FIG. (a), an initial position of the selecting jack (22) is set at a welt position to ready for non-operation. And, as shown in FIG. (b), when a butt (22a) is pressed by a B presser (27) of a carriage (33), the selecting jack (22) comes into a locked condition by a locking member (30). The selecting jack (22) is sunk into a needle groove (35) in the locked condition and the butt of a knitting needle is also sunk into the needle groove (35) to separate from a knitting cam. When a knitting position or tucking position is selected by a needle selection actuator (25), a selector (23) is driven by a selector cam (24), and a tip (22d) of the selecting jack (22) presses a contact portion (22e) of the selecting jack (22) to move the selecting jack rightward. During the movement, the locking member (30) is drawn to release the locked condition.