A thermal type flowmeter for measuring a flow rate by arranging a measuring element with an exothermic resistor and a temperature measuring resistor being shaped in the side of the surface of a substrate within a fluid passage, wherein cantilever plate parts protruding from a wall face of the fluid passage opposing to the surface of the measuring element to the measuring element side are arranged, a gap is provided between the tip part of the cantilever plate parts in the protruding direction and the measuring element, and the cantilever plate parts are extended from the upstream to the downstream of the measuring element, wherein the measuring element is supported by a support member opposing to the wall face, the support member is arranged so that channels where fluid flows are constituted respectively between a first wall face and the support member and between a second wall face opposing to the first wall face and the support member constituting the fluid passage and so that the measuring element opposes to the first wall face, the cantilever plate parts are made protrude from the second wall face toward the support member, said gap is provided between the tip part of the cantilever plate parts and the support member, and the cantilever plate parts are extended from the upstream to the downstream of the support member wherein plate-like parts are arranged extending from the wall face side to the measuring element side or the support member side beyond the tip part of the cantilever plate parts in the upstream side and the downstream side of the measuring element characterized in that guide parts of a projected or recessed shape which head from the measuring element side to the wall face side as they go close to the measuring element are shaped in the side faces of the plate-like parts (7a, 7b). cantilever plate parts protruding from a wall face of the fluid passage opposing to the surface of the measuring element to the measuring element side are arranged, a gap is provided between the tip part of the cantilever plate parts in the protruding direction and the measuring element, and the cantilever plate parts are extended from the upstream to the downstream of the measuring element, wherein the measuring element is supported by a support member opposing to the wall face, the support member is arranged so that channels where fluid flows are constituted respectively between a first wall face and the support member and between a second wall face opposing to the first wall face and the support member constituting the fluid passage and so that the measuring element opposes to the first wall face, the cantilever plate parts are made protrude from the second wall face toward the support member, said gap is provided between the tip part of the cantilever plate parts and the support member, and the cantilever plate parts are extended from the upstream to the downstream of the support member wherein plate-like parts are arranged extending from the wall face side to the measuring element side or the support member side beyond the tip part of the cantilever plate parts in the upstream side and the downstream side of the measuring element characterized in that guide parts of a projected or recessed shape which head from the measuring element side to the wall face side as they go close to the measuring element are shaped in the side faces of the plate-like parts (7a, 7b).