Work began in 1956 on development of a fully tracked armored personnel carrier (APC) to equip the Japan Ground Self-Defense Force, with two prototypes being completed by Komatsu (the SU-I) and by Mitsubishi (the SU-II) in 1957.

The driver sat at the front-right of the hull, with the bow gunner, armed with a single 7.62 mm M1919 Browning machine gun sitting to his left.

Six troops were carried in a compartment at the rear of the hull, accessed by two doors at the back of the vehicle.

[1] The vehicle was powered by a 160 kilowatts (220 hp) Mitisubishi 8 HA 21 WT V8 diesel engine mounted behind the bow gunner.

[8] Roles included training, with several Type 60s being modified to visually resemble the Soviet BMD-1 airborne infantry fighting vehicles.