The Chichibu Railway Class DeKi 500 (秩父鉄道デキ500形) is a Bo-Bo wheel arrangement DC electric locomotive type operated by the private railway operator Chichibu Railway in Saitama Prefecture, Japan, primarily on freight services, since 1973.

[1] As of 1 April 2016[update], all of the original seven locomotives are in operation.

[1] These locomotives were finished in then-standard blue Chichibu Railway livery from new, as opposed to the brown livery initially carried by earlier classes.

[1] Locomotives DeKi 503 and 504 were delivered in March 1979 ahead of the opening of the Mikajiru Freight Line in October of the same year.

[1] DeKi 507 is unique among the class in being privately owned by Taiheiyo Cement, and its introduction in 1980 allowed the similarly privately owned DeKi 101 to be transferred to Chichibu Railway ownership.