To detect a mixture of a hard ball except a soft ball set to be used, in a ball feeding path of a pitching machine.

A ball feeding apparatus 1 for the pitching machine is composed of: a belt conveyer 13 which comprises the ball feeding path for feeding the soft ball S to a pitching machine 5 and feeds the ball while placing it on an upper belt 13a; a support plate 15 for supporting an upper belt 13a of the conveyer proximately from the back; ball discriminating parts 21 which are installed at intervals smaller than a diameter of the ball on the upstream side of the support plate to press a ball B fed on the support plate 15 by the upper belt 13a towards the upper belt 13a and the support plate 15 and pass a ball by deforming it when the fed ball is the soft ball S or are displaced against a spring 24 when the ball is the hard ball; and a limit switch 29 for detecting the displacement of the ball discriminating parts 21 and stopping the belt conveyer 13 when the presence of the hard ball is detected.