In police interviews played to Preston Crown Court on Wednesday, Roache said he was "a very peaceful person" who would "never do anything like that".
The actor, who has played Ken Barlow in the soap for over fifty years, was arrested and cautioned at his home in Wilmslow, Cheshire, on the morning of 1 May last year.
He was told he had been accused of raping a 15-year-old girl at his former home in Lancashire in 1967.
When the officer cautioned him, Roache replied: "I'm absolutely surprised and amazed."
He was then taken in an unmarked vehicle to a police station where the circumstances of the allegations were outlined. In the presence of his solicitor, he was told the reason for his arrest and his legal rights.
The interviewing detective said the complainant claimed she had been raped in two different properties by Roache.
"Well, I totally deny that," he said. "I deny that ever took place."
Roache said he did not recognise the name or maiden name of his accuser.
He said he was not engaged in sexual activity with girls around the age of 15 while living in the area.
He added: "It's against my nature. I am a very peaceful person. I would never do anything like that."
Asked whether he could remember if any young girls would "come on to you", he said women would but young girls were just "excited" children. Roache said there may have been a "flirty comment" in getting an autograph "but not in a sustained way".
The detective asked: "Can you think of any reason why this girl would lie to the police about what had happened?"
Roache replied: "No. People nowadays ... it is happening quite a lot ... some people want a bit of sensation, a bit of publicity."
A lot of people are coming out accusing celebrities, for various reasons...I don't know what the motivation would be.
Roache was later charged with two counts of rape and the publicity that followed led to four women coming forward to say he indecently assaulted them.
He denies all the allegations involving the five complainants who were aged 16 and under on dates between 1965 and 1971.
The accounts of the rapes given by Roache's accuser were put to him in detail.
It is alleged that on the first occasion he showed the girl into a bedroom with a double bed, followed her in, spun her around and pushed her on to the bed.
"I would never do that to anybody, I would remember that quite clearly," Roache told the officer.
Details of the second alleged rape on the same victim at a different property some time later were then put to Roache during the interview.
Roache said "it strikes me a little strange" that a girl he is alleged to have raped before would go near him again.
"I'm a very gentle, peaceful person and I would never do anything that would offend anyone," he added.
He was asked if he could give "any reason" why she would make these claims.
Roache said: "The climate of what's happening at the moment, a lot of people are coming out accusing celebrities, for various reasons, and I don't know what her motivation is.
"I can only surmise there's some hope of selling articles to the newspaper, a moment of fame. I don't know what the motivation would be and I'm absolutely horrified at the whole thing.
"I was always polite and friendly with the viewers and people in the street. I have no idea why she would come up with this."
At the end of the first police interview, Roache added: "I'm denying it totally. I have no idea why these allegations are being made.
"I'm absolutely staggered, absolutely staggered, I don't really know what her motivation is."
The trial continues.