Police who seized the computer of a Liversedge man found thousands of indecent images of children on it, a court heard.
Ian Davison, 60, of Union Road, had more than 21,500 pictures on his computer and police also found films of children taken from the street.
Davison admitted 23 charges of making and taking indecent images when he appeared at Kirklees Magistrates’ Court.
Prosecuting, Linda Fowler, said that in 2009 police became aware of a particular website where users could access child pornography.
They tracked one of the IP addresses to Davison and searched his home.
Mrs Fowler said: “His computers were seized and he admitted the downloading of indecent images of children.
“He said he had been looking at adult pornography and started to look at indecent child images.”
The court heard that of the images seized, 421 were graded at the most serious level of five.
A total of 350 movies of children were also found in Davison’s possession.
Mrs Fowler added: “A number of images of children have been filmed from the street by this defendant.”
Davison was committed for sentence at Leeds Crown Court.
He will appear there on August 15 and was granted unconditional bail.