First Amendment to Sub-Advisory Agreement, dated February 28, 2018, between Hennessy Advisors, Inc. and SPARX Asset Management Co., Ltd. (for the Hennessy Japan Fund and the Hennessy Japan Small Cap Fund)

Exhibit 10.4

FIRST AMENDMENT TO

SUB-ADVISORY AGREEMENT

THIS FIRST AMENDMENT TO SUB-ADVISORY AGREEMENT (this “Amendment”) is made and entered into effective as of February 28, 2018, by and between Hennessy Advisors, Inc., a California corporation (“Manager”), and SPARX Asset Management Co., Ltd., a corporation organized under the laws of Japan (“Sub-Adviser”).

RECITALS

WHEREAS, Manager and Sub-Adviser previously entered into a Sub-Advisory Agreement, effective as of February 28, 2014 (the “Agreement”) pursuant to which Sub-Adviser agreed to render investment advisory and other services to Manager and the Funds (as defined in the Agreement) pursuant to the Agreement; and

WHEREAS, Manager and Sub-Adviser desire to amend certain terms of the Agreement as set forth herein.

AGREEMENT

NOW, THEREFORE, Manager and Sub-Adviser agree as follows:

* * *

(Signatures on next page.)

IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be executed by their duly authorized officers as of the date first mentioned above.

Signature Page to First Amendment to Sub-Advisory Agreement

SCHEDULE A

(as of February 28, 2018)

Schedule A