Police did not name the suspect but media and the website of Sugarbook say the founder is 34-year-old Darren Chan.
Sugarbook promises to link younger women with older men who are expected to provide financial support.
Last week the app boasted that thousands of students, which it called “sugarbabies”, had joined.
Access was then blocked after an outcry.
The app’s founder was arrested in Kuala Lumpur. He was released, but the Straits Times said he was rearrested on Thursday.
He is not thought to have commented since his arrest but on Tuesday tweeted: “Although we do not have any form of nudity, adult content nor prostitution, we’ve lost the battle.
“We believe that our Malaysian government knows what’s best for the people.”
The app’s slogan is “where romance meets finance” and it says it offers users a “sugar relationship” in which both people “define what they want in a relationship in exchange for financial support”.
It also says it is “a social networking platform that helps build beneficial relationships with our society’s elite”.
Last week it claimed on Facebook that thousands of students from 10 elite universities in Malaysia were using the app to finance their lifestyles.
“We are investigating the case for publishing or circulating any statement, rumour or report with intent to cause fear or alarm to the public, sharing offensive or menacing content, and prostitution,” police chief Fadzil Ahmat said according to the Straits Times website.
On Tuesday the Sugarbook website was blocked by Malaysian authorities who said it had breached internet regulations.
Founded in 2016, the app is used in a number of countries including Singapore, Thailand and the US.