Lynnett Alptekin, 40, pillaged the Carlton Technologies' bank balance for four years - ruining its credit rating when its directors were forced to take out loans to keep going.
Derby Crown Court heard the accountant - who is currently 31 weeks pregnant - spent the money on a house, a car and trips to Turkey.
Carlton Technologies director Max Crompton took out a £250,000 loan against his own home and made a member of staff redundant to cover the losses caused by Alptekin.
Aaron Dinnes, prosecuting, described how the defendant set up 10 different bank accounts - naming them as suppliers the company used so the payments would not seem out of place.
Mr Dinnes said: “Payments were made across 10 different accounts belonging to the defendant - the total amount stolen was £362,103.
“Payments were made in various amounts ranging from various amounts ranging from £60 to over £3,000.”
Alptekin’s crimes were not discovered until almost a year after she left the firm - when a finance officer tried to pay a supplier and they never received the payment - which went to one of the defendant’s accounts.
Between 2015 and 2019 stole 246 times from the firm.
Max Crompton, director of Carlton Technologies read out a statement to the court in which he said: “I cannot put into words the effect this fraud has had on my family and business.”
The court heard the firm's credit rating and reputation with suppliers was now “destroyed” as a result of Alptekin’s fraud and the extra borrowing it had to resort to survive.
Alptekin, of Osmaston Road, Derby, admitted fraud by abuse of position.
Recorder Juston Wigoder told her: “You realised it was easy to steal from them and began with small amounts which grew larger and larger.
“This was sophisticated offending in a number of ways.”
Alptekin’s defence counsel asked for a deferred sentence, so she would not have to give birth while in prison.
However the judge, jailing Alptekin for three years, said: “I’m afraid I’ve come to the conclusion that the only appropriate sentence is one of immediate imprisonment.
“I do that with a heavy heart in light of your condition.”