Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2021	Jan. 28, 2022	Apr. 30, 2021
Cover [Abstract]
Entity Central Index Key	0000036840
Current Fiscal Year End Date	--10-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Oct. 31, 2021
Entity File Number	000-25043
Entity Registrant Name	FIRST REAL ESTATE INVESTMENT TRUST OF NEW JERSEY, INC.
Entity Incorporation State Country Name	MD
Entity Tax Identification Number	22-1697095
Entity Address, Address Line One	505 Main Street
Entity Address, City or Town	Hackensack
Entity Address, State or Province	NJ
Entity Address, Postal Zip Code	07601
City Area Code	201
Local Phone Number	488-6400
Title of 12(b) Security	Common stock, par value $0.01 per share
Trading Symbol	FREVS
Name of Exchange on which Security is Registered	NONE
Is Entity a Well-known Seasoned Issuer?	No
Is Entity a Voluntary Filer?	No
Auditor Attestation Flag	false
Entitys Reporting Status Current	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 105
Entity Common Stock, Shares Outstanding		6,860,048