The trains were converted from former Keio 5000 series EMU cars between 1987 and 1994.

[4] The trains were purchased from Keio Corporation and introduced between 1987 and 1994.

[3] The motored cars were mounted on former Tobu Railway and Odakyu EMU bogies to match the Iyotetsu track gauge of 1,067 mm (3 ft 6 in), as the trains originally ran on Keio 1,372 mm (4 ft 6 in) gauge.

As of November 2023, only 19 vehicles remain registered in the fleet.

[1] In September 2015, two 700 series cars were sold to the Choshi Electric Railway in Chiba Prefecture for 1.3 million yen.