The　have　studied　the　magnetocaloric　effect　around　room　temperature　of　LaFe11.17-xCo0.78　Si1.05Bx(x=0,　0.1,　0.2,　0.3,)　alloys　using　commercial　pure　material.　The　element　B　is　interstitial　atom.　The　phase　transition　temperature　increase　from　277　K　for　x=0　to　289　K　for　x=0.3　with　increasing　B　content.　Simultaneity,　the　magnetic　entropy　change　and　adiabatic　temperature　change　which　measured　directly　also　increase　as　increasing　B　content,　and　show　large　magnetocaloric　effect　at　lower　magnetic　field.　Measurements　also　indicate　that　both　thermal　hysteresis　and　hysteresis　are　rather　small.