NOVELTY - An upconversion-type fluorescent substance comprises trivalent metal-ytterbium-pentavalent metal oxide-containing ceramic compound (A1) (I), trivalent metal-ytterbium-pentavalent metal oxide-containing ceramic compound (A2) (II), or trivalent metal-ytterbium-pentavalent metal oxide-containing ceramic compound (A3) (III).    USE - Upconversion-type fluorescent substance is used for electrical or electronic device. Uses include but are not limited to solar cell, analytical instrument, laser oscillation apparatus, light-emitting device, memory device, measuring device, optical information processing apparatus, apparatus for imaging biological cell, laser projector, digital printing system, etc.    ADVANTAGE - The upconversion-type fluorescent substance has excellent chemical stability and strength, and is manufactured by simple method.    DETAILED DESCRIPTION - An upconversion-type fluorescent substance comprises trivalent metal-ytterbium-pentavalent metal oxide-containing ceramic compound (A1) of formula: ((M1)a1(M2)b1Ybc1)(M3)7O19 (I), trivalent metal-ytterbium-pentavalent metal oxide-containing ceramic compound (A2) of formula: ((M1)a2(M2)bYbc2)(M3)O4 (II), or trivalent metal-ytterbium-pentavalent metal oxide-containing ceramic compound (A3) of formula: ((M1)a3(M2)b3Ybc3)3(M3)O7 (III).    a1=0-0.998;    b1+c1=0.002-1;    b1:c1=100:1-1:100;    a1+b1+c1,a2+b2+c2=1,a3+b3+c3=1;    a2=0.5-0.998;    b2+c2=0.002-0.5;    b2:c2=100:1-1:100;    a3=0.3-0.998;    b3+c3=0.002-0.7;    M1=trivalent metal atom having ionic radius of 0.75-1.2 Angstrom excluding erbium, holmium, ytterbium, and thulium;    M2=trivalent metal atom chosen from erbium, holmium, and thulium;and    M3=pentavalent metal atom chosen from tantalum and niobium excluding YTaO4:Er,Yb, LaTaO4:Er,Yb, GdTaO4:Er,Yb, YTaO4:Tm,Yb, YNbO4:Er,Yb, YNbO4:Tm, and Yb.    An INDEPENDENT CLAIM is included for manufacture of upconversion-type fluorescent substance, which involves mixing base material (A) containing compound of trivalent metal (M1) as primary raw material (a1) and compound of pentavalent metal (M3) as secondary raw material (a2), activator raw material compound (B) containing compound of trivalent metal (M2), and photosensitizer raw material compound (C) containing ytterbium compound, obtaining a mixture, baking powder mixture at 800-1500 degrees C, and manufacturing ceramic compound (A1), ceramic compound (A2), or ceramic compound (A3). The content of metal atoms in material (A), and total content of metal atoms in compound (B) and compound (C) of ceramic compound (A1) are 0.2-100 atomic% and 0-99.8 atomic%, respectively, with respect to 100 atomic% of total content of metal atoms in material (A), compound (B), and compound (C). The ratio of metal atoms in compound (B) with respect to compound (C) in ceramic compound (A1) is 100:1-1:100. The number of atoms of pentavalent metal (M3) contained in the material (A) of ceramic compound (A1) is 490-910 with respect to 100 of total number of metal atoms contained in material (A), compound (B), and compound (C). The content of metal atoms in material (A), and total content of metal atoms in compound (B) and compound (C) of ceramic compound (A2) are 0.2-50 atomic% and 50-99.8 atomic%, respectively, with respect to 100 atomic% of total content of metal atoms in material (A), compound (B), and compound (C). The ratio of metal atoms in compound (B) with respect to compound (C) in ceramic compound (A2) is 100:1-1:100. The number of atoms of pentavalent metal (M3) contained in the material (A) of ceramic compound (A2) is 70-130 with respect to 100 of total number of metal atoms contained in material (A), compound (B), and compound (C). The content of metal atoms in material (A), and total content of metal atoms in compound (B) and compound (C) of ceramic compound (A3) are 0.2-70 atomic% and 30-99.8 atomic%, respectively, with respect to 100 atomic% of total content of metal atoms in material (A), compound (B), and compound (C). The ratio of metal atoms in compound (B) with respect to compound (C) in ceramic compound (A3) is 100:1-1:100. The number of atoms of pentavalent metal (M3) contained in the material (A) of ceramic compound (A3) is 23-43 with respect to 100 of total number of metal atoms contained in material (A), compound (B), and compound (C).