13. Is there a ban on the use of state resources in favour or against a political party or candidate?

Source: 
政治資金規正法, 1948 (2022改正)
Political Funds Control Act, 1948 (as amended by Act No.68 of 2022)

第二十二条の九 国若しくは地方公共団体の公務員又は行政執行法人若しくは特定地方独立行政法人の職員で次に掲げるものは、その地位を利用して、政治活動に関する寄附を求め、若しくは受け、若しくは自己以外の者がする政治活動に関する寄附に関与し、又は政治資金パーティーに対価を支払つて参加することを求め、若しくは政治資金パーティーの対価の支払を受け、若しくは自己以外の者がするこれらの行為に関与してはならない。

Article 22-9 No public official of the national or local governments, or employee of an administrative enforcement corporation or specified local independent administrative corporation, shall, by taking advantage of their position, solicit or accept donations for political activities, participate in donations for political activities made by persons other than themselves, solicit participation in political fund-raising parties in exchange for payment, accept payment for participation in such parties, or participate in any of these acts performed by persons other than themselves.

Source: 
放送法, 1950 (2022改正)
Broadcast Act, 1950 (as amended by Act No.68 of 2022)

第四条 放送事業者は、国内放送及び内外放送の放送番組の編集に当たつては、次の各号の定めるところによらなければならない。
二　政治的に公平であること。

Article 4 Broadcasters shall comply with the following provisions when editing domestic broadcasts and domestic and international broadcast programs:
(ii) Political impartiality.

Civil servants cannot solicit donations by taking advantage of their positions.  A broadcaster should be required to be politically impartial.