Filip Ziebicki, who worked at Wade Deacon high, in Widnes, had been given money by pupils for a trip to Alton Towers but this appeared to have gone missing, the General Teaching Council for England heard.
It was supplemented by cash raised by pupils for a local special needs school, said Sarah Page, the presenting officer.
Headteacher Peter Barrie said in a statement that he had been told in March 2002 that "there appeared to be a discrepancy in the money collected for the trip".
He said a shortfall of pound;164.84 in trip funds was apparent, with each pupil having paid pound;18.50.
"I suspected that some of the money must have been replaced by the Brookfield school fund," said Mr Barrie.
He said money raised from a Valentine's dance was also suspected to have been mixed up in the fund.
Mr Barrie added that money collected for school trips had to be recorded before it was banked and all receipts kept but Mr Ziebicki, who had worked at the school since 1979, failed to do this.
"Bags of money, coinage of low denominations, were found in his garage," Ms Page told the hearing.
Mr Ziebicki was suspended in March 2002 and later resigned.
He accepted allegations at an investigations committee that he had used sums of money from other sources to fund the trip and had been lax in his organisation.
At the meeting, one of Mr Ziebicki's colleagues said he was feeling very low at the time, and that his organisation skills had become worse.
Carole Regan, chair of the conduct committee, said: "Although the school had a legitimate basis for its claim it does not follow that he is guilty of gross misconduct.
"There is no evidence that Mr Ziebicki acted dishonestly."