Is Final Fantasy IV Available on Nintendo GameCube? No

No. Final Fantasy IV has never been officially released on the Nintendo GameCube.

Platforms It Has Released On

• Original: Super Famicom / SNES (1991)
• Ports/Remakes: PlayStation (1997), WonderSwan Color (2002), Game Boy Advance (2005), Nintendo DS (2007 - 3D remake), PSP (2011 - Complete Collection), iOS/Android (2012), Steam (2014), PS4/Switch/Xbox One (2021 - Pixel Remaster)

The GameCube received Final Fantasy Crystal Chronicles (spin-off) and Final Fantasy XI (MMO, Japan only), but no mainline numbered FF until the Pixel Remasters on Switch.