An electric heat sealer for sealing workpieces such as plastic bags or the like includes a casing defining a battery chamber, a press bar pivotally connected to the casing, a sealing mechanism supported on a compression spring in a spring holder inside the casing, and a safety device. The sealing mechanism is electrically connected to produce heat for sealing the workpiece being put thereon when the press bar pressed against the sealing mechanism. The safety device breaks the electrical circuit when the apparatus is not in use.