A turbo fan, comprising: a main plate for rotation in a rotational direction about a rotational axis; and a plurality of blades arranged at intervals around the rotational axis of the main plate, at least one blade including: a first blade section having a leading end and a trailing end; a second blade section having a leading end and a trailing end, wherein the first blade section is between the main plate and the second blade section; and a third blade section (A3') having a leading end (L3') and a trailing end, wherein the third blade section (A3') is between the first blade section and the second blade section, wherein the trailing end of the first blade section is disposed more towards the rotational direction than the trailing end of the second blade section, wherein the trailing end of the third blade section (A3') is disposed between the trailing end of the first blade section and the trailing end of the second blade section, characterized in that the leading end (L3') of the third blade section (A3') is disposed more towards a negative pressure side of the blade than the leading end of the first blade section, and in that the leading end of the first blade section is disposed between the leading end of the second blade section and the leading end (L3') of the third blade section (A3'). a main plate for rotation in a rotational direction about a rotational axis; and a plurality of blades arranged at intervals around the rotational axis of the main plate, at least one blade including: a first blade section having a leading end and a trailing end; a second blade section having a leading end and a trailing end, wherein the first blade section is between the main plate and the second blade section; and a third blade section (A3') having a leading end (L3') and a trailing end, wherein the third blade section (A3') is between the first blade section and the second blade section, wherein the trailing end of the first blade section is disposed more towards the rotational direction than the trailing end of the second blade section, wherein the trailing end of the third blade section (A3') is disposed between the trailing end of the first blade section and the trailing end of the second blade section, characterized in that the leading end (L3') of the third blade section (A3') is disposed more towards a negative pressure side of the blade than the leading end of the first blade section, and in that the leading end of the first blade section is disposed between the leading end of the second blade section and the leading end (L3') of the third blade section (A3'). a first blade section having a leading end and a trailing end; a second blade section having a leading end and a trailing end, wherein the first blade section is between the main plate and the second blade section; and a third blade section (A3') having a leading end (L3') and a trailing end, wherein the third blade section (A3') is between the first blade section and the second blade section, wherein the trailing end of the first blade section is disposed more towards the rotational direction than the trailing end of the second blade section, wherein the trailing end of the third blade section (A3') is disposed between the trailing end of the first blade section and the trailing end of the second blade section, characterized in that the leading end (L3') of the third blade section (A3') is disposed more towards a negative pressure side of the blade than the leading end of the first blade section, and in that the leading end of the first blade section is disposed between the leading end of the second blade section and the leading end (L3') of the third blade section (A3').