Police said the accident happened on the Chokchai-Chaimongkol road in Ban Sao Diew village in Tambon Tha Ang at 7.28pm.
The cyclist was identified as Krissada Phumalee, 34. He was wearing a cyclist exercise outfit.
The female car driver, 35, who asked police not to release her name, waited for police at the scene.
Police said the road was often used by bicyclists for exercise during the daytime because the area is dark at night.