Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 13, 2021
Document Information Line Items
Entity Registrant Name	OCA ACQUISITION CORP.
Trading Symbol	OCAX
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Central Index Key	0001820175
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Shell Company	true
Entity Ex Transition Period	false
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-39901
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	85-2218652
Entity Address, Address Line One	1345 Avenue of the Americas
Entity Address, Address Line Two	33rd Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10105
City Area Code	(212)
Local Phone Number	201-8533
Security Exchange Name	NASDAQ
Title of 12(b) Security	Class A Common Stock, par value $0.0001 per share
Entity Interactive Data Current	Yes
Class A common stock
Document Information Line Items
Entity Common Stock, Shares Outstanding		14,950,000
Class B common stock
Document Information Line Items
Entity Common Stock, Shares Outstanding		3,737,500