Document And Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2015	Dec. 10, 2015	Mar. 31, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Fiscal Year Focus	2015
Entity Registrant Name	Arch Therapeutics, Inc.
Entity Central Index Key	0001537561
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Trading Symbol	ARTH
Document Period End Date	Sep. 30, 2015
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--09-30
Entity Filer Category	Smaller Reporting Company
Entity Public Float			$ 10,000,000
Entity Common Stock, Shares Outstanding		108,879,552