| Cover | May 31, 2023 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | May 31, 2023 |
| Entity File Number | 001-41309 |
| Entity Registrant Name | FG Merger Corp. |
| Entity Central Index Key | 0001906133 |
| Entity Tax Identification Number | 86-2462502 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 104 S. Walnut Street, Unit 1A |
| Entity Address, City or Town | Itasca |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60143 |
| City Area Code | 847 |
| Local Phone Number | 773-1665 |
| Written Communications | true |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | false |
| Common Stock [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | FGMC |
| Security Exchange Name | NASDAQ |
| Warrants [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Warrants |
| Trading Symbol | FGMCW |
| Security Exchange Name | NASDAQ |
| Units [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Units |
| Trading Symbol | FGMCU |
| Security Exchange Name | NASDAQ |
