A gear unit 40 includes: a sprocket 32 including pins 31 provided on a periphery thereof and a final gear 42; and one or more transmission gears disposed between a drive motor 33 and the final gear 42. The pins 31 engage with feed holes provided at equal pitches in a carrier tape. A sensor 48 which detects an angle is provided to face a transmission gear, of the one or more transmission gears, of which a rotation ratio to the final gear 42 is 1:N (N is a positive integer).