The pilot stated that he accumulated 26 hours of flight time in the accident airplane about 2 years prior to the accident, but had not flown the accident airplane since. About 1 week prior to the accident, the pilot obtained his airplane multiengine rating in a different make and model than the accident airplane. The pilot stated that the purpose of the accident flight was to perform full-stop landings in order to familiarize himself with the airplane. While on the downwind leg of the traffic pattern for the first landing, he was cleared by the air traffic control tower for a "touch-and-go." After the airplane touched down, the pilot applied full power, and intended to retract the wing flaps, but inadvertently retracted the landing gear instead. The landing gear "immediately" collapsed, and the airplane slid to a stop on its underside. Both wings were substantially damaged. The pilot stated there were no mechanical malfunctions or failures, and that the accident might have been prevented if he had declined the touch-and-go landing, and had taken time to become more familiar with the locations of the landing gear and flap controls. He also stated that he had recently trained in an airplane with a "different layout," and his "sense memory for the controls was wrong."