An often-repeated myth is that the productions of both this film and Los siete samuráis (1954) nearly drove Toho into bankruptcy. This neglects to mention a third Toho film made that year, Miyamoto Musashi (1954). All three of them were the most expensive Japanese films made up to that point and big financial risks for Toho. However, there is little evidence to suggest that Toho was ever at risk for bankruptcy. Toho released a total of 68 feature films that year, the most successful of which were "Seven Samurai", "Samurai I: Musashi Miyamoto", and "Godzilla", in that order.
Toho's sound department tried numerous animal roars for Godzilla, but felt they were unsuitable for an animal of such immense size. The film's music director, Akira Ifukube, came up with Godzilla's roar by rubbing a coarse resin-coated leather glove up and down the strings of a contrabass (double bass), and reverberating the recorded sound. Also, Godzilla's thunderous footsteps were made by beating a kettle drum with a knotted rope.
Stop-motion animation was rejected for this film because of the amount of time that it would take. Special effects director Eiji Tsuburaya sincerely wanted to use this method, but he faced the grim reality that there was not enough people in Japan with enough experience in this technique and that Toho would never give him the time he needed due to their tight production schedules. Tsuburaya had to pioneer the techniques of suitmation which would make the production more feasible, though no less difficult. One benefit of this method was in depicting Godzilla's enormous size since, if a stop-motion puppet had been used, it would have required miniatures at a much smaller scale, resulting in less detail and destruction. The film does makes use of stop-motion animation to enhance a few brief scenes in which a vehicle crashes and Godzilla's tail twitches.
One of the most famous legends regarding the production of this film has director Ishirô Honda and special effects director Eiji Tsuburaya on the observation deck of one of Tokyo's buildings. They were planning Godzilla's path of destruction when visitors on the deck overheard their conversation and became concerned. The pair was stopped by the authorities and questioned.
The Godzilla suit used for the film was so hot inside that suit actor Haruo Nakajima would frequently faint. According to Nakajima, temperatures inside the suit reached up to 60 degrees Celsius (or 140 degrees Fahrenheit) due to the hot studio lights and it was not uncommon for one cup of Nakajima's sweat to be drained from the suit. Special effects director Teruyoshi Nakano, who worked with Nakajima in the later Godzilla films, described his admiration for the actor, stating "Inside the Godzilla suit, it was very dark, lonely, and isolated. Usually the person who wears the suit becomes nervous and anxious. During summertime it's very hot, it can become hell in there. But Mr. Nakajima always persevered. He acted in the suit underwater, he was buried underground, he withstood pyrotechnic explosions...and through it all he was always Godzilla."
Haruo Nakajima: A man inside the electric room (just before director Ishirô Honda throws the switch). He also appears as one of Hagiwara's fellow reporters in the newspaper office.
Ishirô Honda: The man in the electric room who throws the switch, thus activating the 300,000-volt power lines in order to kill Godzilla by electrocuting him.